Review IIIIIIII II

J BiomedSci 1994;1:65-82

Departmentof Microbiology, The Mount SinaiSchoolof Medicine, NewYork, N.Y., USA

e s o o * o e ~ * o ~ J o ~ * * o o ~ * ~ o l o o

KeyWords Growth factor Ligand Oncogenesis Phosphotyrosine Receptor

J * ~ o o * , o

o ~ • o e a * o o o ~ o o

Oncogenes, Protein Tyrosine Kinases, and Signal Transduction

* ~ o l * o o l o o m * J . o o o . . o l m * ol • e * o e / i o o l o o t * o o o t * o i Q * o o • o l a . Qoaolo*~ooo***o ~ool • *oo • . l l • o l o * * o o o g o * •

olo

Abstract Many oncogenes encode protein tyrosine kinases (PTKs). Oncogenic mutations of these genes invariably result in constitutive activation of these PTKs. Autophosphorylation of the PTKs and tyrosine phosphorylation of their cellular substrates are essential events for transmission of the mitogenic signal into cells. The recent discovery of the characteristic amino acid sequences, of the s r c homology domains 2 and 3 (SH2 and SH3), and extensive studies on proteins containing the SH2 and SH3 domains have revealed that protein tyrosine-phosphorylation of PTKs provides phosphotyrosine sites for SH2 binding and allows extracellular signals to be relayed into the nucleus through a chain of protein-protein interactions mediated by the SH2 and SH3 domains. Studies on oncogenes, PTKs and SH2/SH3-containing proteins have made a tremendous contribution to our understanding of the mechanisms for the control of cell growth, oncogenesis, and signal transduction. This review is intended to provide an outline of the most recent progress in the study of signal transduction by PTKs. ~oe.t...o.

~.oos i.o~...

Cellular proliferation and differentiation are normally regulated by growth factors through transmembrane receptors with intrinsic protein tyrosine kinase (PTK) activity. These receptor-type PTKs (RPTKs) have a common structural configuration. They all consist of an extracelllar ligand-binding domain, a single transmembrane (TM) domain, and an intracellular domain harboring the tyrosine kinase catalytic sequence [231]. The mitogenic signals of growth factors are transmitted into cells through their cognate receptors by activating their intrinsic PTK activity. The PTK activity is absolutely required for the signal transduction. Autophosphorylation of the activated receptors is usually the earliest response upon ligand stimulation. Ligand-induced oligomerization and intermolecu-

Received: June 2 , 1 9 9 3 Accepted: June25,1993

lar phosphorylation of RPTKs are considered to be a general mechanism for their activation [16, 204, 259]. Aside from activation of the catalytic PTK activity, little was known about the functional significance of autophosphor3dation until recently. Studies in the past several years on proteins containing s r c homology domains 2 and 3 (SH2 and SH3) have revealed that PTK autophosphorylation creates sites (phosphotyrosine motifs) for SH2 binding and thus initiates a chain of protein-protein interactions, fulfilling the signal transmission from extracellular growth factor to nucleus resulting in gene activation, DNA synthesis and cell proliferation or differentiation [25, 106].

Professor L u - H a i W a n g , P h D Box 1124, D e p a r t m e n t & M i c r o b i o l o g y T h e M o u n t Sinai School o f M e d i c i n e O n e G u s t a v e L. L e v y P l a c e N e w York, N Y 1 0 0 2 9 - 6 5 7 4 ( U S A )

Table 1, RPTK RPTK

Ligand

Oncogene Origin

Reference

EGFR

EGF

v-erbB

AEV-R(ES4) AEV-H

46 255

Neu

NDF

neu

neuroblastoma

79,243

HER3

?

erbB3

110

CSF- 1R

CSF- 1

v-f ms

FeSV

199

Kit

MGF

v-kit

FeSV

10

Ros

?

v-ros

ASV UR2

161,239

Met

HGF

met

osteosarcoma

35

NGFR

NGF NT-3

trk trkB trkC

colon carcinoma

136 105 114

FGFR

aFGF bFGF

f/g bek

196 175

Ret

?

ret

Sea

?

v-sea

PDGFR

PDGF

IR

insulin

human placenta

49,229

IGF-1R

IGF-1

human placenta

230

IRR

?

Flk-2

?

Ltk

?

Axl

?

223 AV S 13

214 249

208

axl

hematopoietic celt

143

lymphocyte, neuron

70

myeloid leukemia

166

AEV = Avian erythroblastosis virus; ASV = avian sarcoma virus; CSF = colony-stimulating factor; EGF = epidermal growth factor; FGF = fibroblast growth factor; FeSV = feline sarcoma virus; HGF = hepatocyte growth factor; IGF = insulin-like growth factor; IRR = insulin-receptor-relatedreceptor; NDF = Neu differentiation factor, NGF = nerve growth factor; NT = neurotrophin; MGF = mastocyte growth factor; PDGF = platelet-derived growth factor.

Regulation of Cell Growth by PTKs The importance of the control of cell growth by growth factors and the RPTKs is best exemplified by the finding that more than a dozen oncogenes have been documented to be altered cellular RPTKs (table 1). Structural and functional alterations of RPTKs invariably lead to subversion of the normal regulation of cell growth [1]. Truncation, internal deletion, point mutation and amplification of RPTK genes have been demonstrated to be common mechanisms for constitutive activation of RPTKs, which consequently promote cell transformation in vitro and oncogenicity in vivo [ 100, 244].

66

Liu/Wang

The first example is the oncogenic counterpart of epidermal growth factor (EGF) receptor (EGFR), v-erbB, which was found to arise from c-erbB by truncation of almost the entire extracellular (EC) sequence and deletion of the C-terminal 34 amino acids (aa) including one major autophosphorylation site [46]. In addition, v-erbB harbors multiple point mutations in comparison with c-erbB. These structural changes render v-erbB constitutively active in its kinase activity and oncogenicity [ 138.209]. A second example of a truncated RPTK gene is v-fms transduced by the Gardner-Amstein strain of feline sarcoma virus. The concogene codes for a mutant version of colony-stimulating factor (CSF-1) receptor (CSF-1R; table 1). The v-fms oncoprotein is synthesized as a precursor fusion protein, gag-fms, which is subsequently cleaved and processed into gpl40 v'fms. In contrast to the v-erbB product, gp140 v-/ms appears to contain the complete ligand-binding domain of the CSF-1R [ 191]. The C-terminal 40 aa in the CSF- 1R have been replaced by 11 irrelevant residues in v-fms, including one t~a'osine residue. Similar ot the v-erbB product, this carboxyl terminal alteration may contribute to the increased tyrosine kinase activity and oncogenicity [199]. Another example of transduced RPTK genes comes from the discovery of v-ros, an oncogene originally found in avian sarcoma virus UR2 [7, 161,239, 240]. The protooncogene c-ros encodes a RPTK-like molecule [11, 28, 142, 160, 161 ]. Similar to v-erbB, v-ros has lost all but 7 aa of its EC domain and also has an altered carboxyl sequence [160, 162]. Like v-fins, v-ros is fused in-frame to the viral gag sequence. The resulting oncoprotein P68gag-r°s is constitutive in kinase activity and is highly transforming and oncogenic [84, 85]. Recent studies showed that c-ros was expressed in kidney and intestines and suggested that it may be important for both development and mature functions of those organs [29, 216,225]. A putative ligand for this RPTK-like molecule remains to be defined. Ros is most homologous to the sevenless protein of Drosophila melanogaster, the insulin receptor (IR) and the insulin-like growth factor-1 (IGF-1) receptor (IGF-1R) in their PTK domains [11, 28, 141,239]. Our studies on the human IR and IGFR and their mutants have also shown that these RPTKs indeed have cell-transforming and oncogenic potential [ 120, 121, 241 ]. The met oncogene was found in carcinogen-treated human osteosarcoma cells and seems to be activated by gene rearrangement such that a DNA segment from human chromosome 1 joins the 5" truncated c-met gene [35, 174, 224]. The fusion protein expressed from the met oncogene is a tyrosine-phosphorylated doublet of 60/65

Signal Transduction by Protein Tyrosine Kinases

kD as opposed to the 165- and 140-kD proteins encoded by the c-met proto-oncogene [224]. c-met proto-oncogene may be the prototype of a new class of tyrosine receptor with a heterodimeric subunit structure consisting of a 50kD c~subunit disulfide-linked to a 145-kD ~3subunit [64, 65]. The c-met proto-oncogene has been found to be amplified and overexpressed both in the GTL-16 gastric carcinoma cell line and in transfected NIH 3T3 cells [174]. Evidence for the transforming capability of the amplified c-met gene has been derived from transfection of NIH 3T3 cells with normal cellular DNA where cells from spontaneously occurring foci were found to contain a 4- to 8-fold amplification of c-met and at least a 20-tbld overexpression of a normal c-met transcript [36]. A recent finding showed that improper processing of Met precursor could cause oncogenic activation [152]. The Met precursor, which is normally cleaved into two subunits, is not processed in a protease-deficient tumor cell line LoVo. As a result, PTK activity of the uncleaved Met is constitutively activated. This may represent a new mechanism for constitutive activation of the RPTK. It was recently shown that the ligand for c-met turned out to be the hepatocyte growth factor (HGF) [I 8]. More extensive truncation and deletion are present in another retroviral oncogene, v-kit, which corresponds to c-kit transduced by the Hardy-Zuckerman-4 strain of feline sarcoma virus [10]. Compared with c-kit, v-kit has lost the entire EC and TM domains. The C-terminal 49 aa of c-kit were replaced by 5 unrelated residues in v-kit, again including the deletion of a potential autophosphorylation site [258]. Unlike the oncoprotein encoded by verbB, v-fins or v-ros, the v-kit gene product becomes associated with plasma membrane via the myristoylated gag sequence fused at the N-terminus of v-kit [10]. c-kit has been demonstrated to be the receptor for mastocyte growth factor (MGF) [37, 56, 83, 248]. The above examples suggest that truncation of the extracellular domains and/or deletion of the C-terminal tails remove negative regulatory elements, resulting in constitutive activation of erbB, fins, ros, and kit. A point mutation, rather than deletions or truncations, is found to be responsible for oncogenic activation of neu, a carcinogen-induced oncogene found in rat neuroblastoma [203]. A single point mutation of valine to glutamic acid in the TM sequence results in constitutive dimerization of the Neu receptor to give higher affinity for ligand binding [8]. There appear to be several ligands for the Neu receptor as demonstrated recently from cloned cDNAs coding for the putative ligands [79, 177, 243].

The oncogene trk was originally isolated from a human colon carcinoma cDNA library. This oncogene was generated by somatic rearrangement that resulted in fusion of the trk PTK sequence including the TM domain with a truncated nonmuscle tropomyosin molecule [ 136]. Protooncogene c-trk encodes a receptor molecule with a ligandbinding domain which is replaced in the oncogenic trkby a tropomyosin sequence [41, 137]. In this case, truncation and fusion to nonmuscle tropomyosin activated the oncogenic potential of c-trk, although other mechanisms like point mutation(s), deletion(s) and duplication(s) of the kinase domain could also activate its oncogenic potential [40]. It is now known that the c-trk product is a high-affinity nerve growth factor (NGF) receptor (NGFR) [104]. Several different forms of trk genes have been cloned recently and they code for a family of receptors with different specificities for a class of neurotrophic factors [105, 114]. The ret oncogene was activated by recombination between two unlinked segments of human DNA, probably during the transfection of NIH 3T3 cells with DNA isolated from a human T cell lymphoma [223]. This oncogene encodes a fusion protein consisting of an amino terminal part from an unknown protein sequence and the ret PTK including the TM domain. Similar to other RPTKs, and RPTK ocogenes ros, met, and trk, the regulatory EC domain of c-ret has been replaced by a novel sequence, presumably causing constitutive activation of the tyrosine kinase activity. As mentioned above, by truncation of the N-terminal EC domain mad fusion of the remaining j3 subunit of the human IR and IGFR to the retroviral gag sequence, the resulting Gag-IR and Gag-IGFR fusion receptors are constitutively activated and are capable of efficiently transforming cells in vitro and inducing tumors in vivo [120, 121,180, 241]. In both cases, the entire TM and cytoplasmic domains including the PTK regions are identical to their corresponding native receptors. Whether the activation of PTK activity is solely responsible for the oncogenic activation or whether there may be qualitative differences in signaling processes is unclear at present. Mutational studies on the C-termini of human IR and IGFR have shown that the C-terminus of IR has a negative modulatory effect on its mitogenic activity but has virtually no effect on the PTK activity [128]. By contrast, the C-terminus of IGFR has a positive effect on its transforming potential and PTK activity [ 122]. The oncogenic RPTKs and their normal counterparts have provided informative clues for understanding the mechanisms of activation of normal growth factor receptors. They also offer invaluable tools for studying signal

67

Table2. Proteins containing SH2 and/or SH3 domains

ABPlp

actin binding

65

--SH3....

47

CDC25 Crk Csk FUS 1 GAP Grb2 Grb7 HS 1 ISGF-3c~ Myo 1B Myo 1L Nck PI3K p85

RAS pathway proto-oncogne src kinase yeast fusion GTPase activating PTK signaling EGFR signaling? ? IFN signaling actin binding actin binding PTK signaling PI3K subunit

? 35 50 ? 120 25 ? 75 84, 91, 113 ? ? ? 85

- -3H3- ---SH2-SH3-SH3---SH3-Sh2--PTK - -SH 3. . . . . . --SH2-SH3-SH2--GA --SH3-SH2-SH3--GH- -SH2- -LHL--SH3--SH3-SH2.... SH3-.... SH3---SH3-SH3-SH3-SH2--SH3-SH2-SH2--

21 144 197 228 227, 234 33, 123, 139, 170, 211 133 101 59 87 88 31, 115, 119, 148, 173 53, 171, 213

PLC-T PTP 1C

phospholipase phosphatase

140 67?

PLC-SH2-SH2-SH3-PLC - -SH2-SH2-PTPase--

218,220, 221 206

Shc

PTK signaling

46, 52, 66

--CH----SH2--

178

Spectrin Tensin Vav

membrane protein actin binding PTK signaling

? 90 95

. . . . . SH3-. . . . . SH2---SH3-SH2-SH3-

242 44 96

ZAP-70 p55

TCR signaling membrane protein

70 55

-SH2-SH2-PTK .... SH3--

27 194

p47 p67 p85

NADPH oxidase NADPH oxidase actin binding

47 67 85

--SH3--SH3----SH3--SH3--. . . . . SH3--

235 116 252

src-like kinase (e.g.fps, yes, abl) are not listed. For their structures, see references 76 and 195. ISGF3ct has three different components, p84/91 and p 113. Shc protein has three different species as indicated. Relative positions of SH2 and SH3 domains in the proteins are indicated, but the size of these proteins are not shown in scale. PTK = protein tyrosine kinase domain; GA = ras GTPase-activating domain; GH = GAP-homologous domain; HLH = helix-loop-helix domain; PLC = phospolipase C; PTPase = protein tyrosine phosphatase domain, CH = collagen homology domain, Myo = myosin; EGFR = eidermat growth factor receptor; IFN = interferon; PI3K = phosphatidylinositol-3 kinase; TCR = T cell receptor.

transduction in the process o f cell transtbrmation as well as their respective physiological functions. A separate group o f oncogenic PTKs, the nonreceptor PTKs, such as src, fps/fes, abl, yes, and so on, have also contributed tremendously to our understanding o f the mechanisms for cellular transformation and tumorigenesis [12, 86]. The accumulated evidence clearly suggests that protein tyrosine phosphorylation plays a crucial role in growth control and oncogenesis.

68

Liu/Wang

Signal Transduction by PTKs Although molecular cloning o f genes encoding PTKs, including R P T K s and nonreceptor P T K s (e.g. the src family), has led to tremendous advances in understanding the structural alterations involved in constitutive activation o f tyrosine kinase activity and oncogenic potential [86, 231], not m u c h is known about how the activated P T K s achieve their ultimate biological effects, namely,

Signal Transduction by Protein Tyrosine Kinases

cell transformation and tumorigenicity. Since kinase activity is absolutely required for the function of PTK oncogenes, cellular substrates of the activated PTKs are logically the molecules that relay the mitogenic signals in the signaling pathways and lead to cell transformation. A great deal of effort has been directed to looking for tyrosine-phosphorylated cellular proteins using antiphosphotyrosine antibodies [57, 66, 90, 91, 190, 238]. A wide spectrum of cellular tyrosine phosphoproteins have been described [73, 86, 89]. However, their molecular identities are rarely known, let alone their functions. A new era began for the study of signal transduction when the noncatalytic regions of src-like kinases, src homology domains 2 and 3 (SH2 and SH3), were implicated in directing protein-protein interactions [94, 144, 200, 218]. Since then, more than 20 proteins have been reported to contain SH2 and/or SH3 domains (table 2). There is increasing evidence indicating that these noncatalytic domains are of primary importance in mediating cellular protein-protein interactions, and participate in signal transmission [for reviews see ref. 25, 176]. Recent progress in the study of signal transduction by PTKs is discussed below and schematized in figure 1.

SH2 and SH3 Domains Studies on cytoplasmic PTKs, such as src, fps/fes, abI, yes, fyn, Ick, fgr, have revealed, in addition to the conserved kinase domain, two other conserved noncatalytic regions [76, 144, 200]. One of the noncatalytic regions lying upstream of the P T K domain in src and fps was designated SH2 [200], the other was later designated SH3 [94, 106, 144, 218]. The importance of the SH2/SH3 domains was clearly recognized when Mayer et al. [144] discovered a unique retroviral oncogene, v-crk, which had no PTK catalytic sequences but only SH2 (B+C box) and SH3 (A box) domains. The SH2 domain consists of about 100 aa which have been found in nonreceptor PTKs and in many other seemingly unrelated proteins (table 2). Evidence has accumulated to clearly show that the SH2 domain binds to protein phosphotyrosine motifs and mediates the interacton between enzyme molecules and their substrates with high affinity and specificity [54, 146]. Mutations in the SH2 region have been shown to cause dramatic changes in biochemical properties and biological functions of these SH2-containing proteins (Src, Abl, and Crk) [ 147]. There are several well-conserved sequence motifs separated by more variable sequence elements inside the SH2 domain [ 106]. Crystal and solution structures of the SH2 domains have been recently reported, and they are characterized

DA

PK

Fig. 1. Schematic representation of PTK signalingpathways. The drawing represents a summary of what is discussed in the text. The question marks indicate that the signalingorientation is not yet well documented or that nothing is known about the downstream signal flow. The blank box represents the PTK domain. The black diamond represents the ligand. IP3 = Inositol-l,4,5-phosphate, DAG = diacylglycerol;PKC = protein kinase C.

by central [3-sheets flanked by two a-helices [ 17, 172, 238]. The central 13-sheets consists of five antiparallel small 13sheets. Binding of the SH2 domain to a phosphotyrosine peptide is suggested to be mediated by the N-terminal whelix, [3-sheet, and intervening loops [ 172, 238]. The highly conserved, positively charged residues (for instance, Arg155, Arg175 and Lys203 in v-src) form a small, shallow cleft and are important in correct positioning and binding of the phosphotyrosine site [238]. Arg155 is par-

69

ticularly important since it recognizes both the phosphate group and the aromatic ring of phosphotyrosine. Arg175 in the sequence FLVRES is strictly conserved among SH2 domains and is involved in specific hydrogen binding with two of the four phosphate oxygens of the phosphotyrosine. Dual SH2-domain-containing proteins might be able to facilitate the binding to dimeric targets, such as activated receptor PTK complex [ 172]. Most SH2-containing proteins are accompanied by a separate sequence motif of about 45 aa known as SH3, which was first described in v-crk and PLC-148 [144, 218]. Subsequently, the SH3 domain has been identified in many proteins that associate with the cytoskeleton and membrane [189] (table2). Several gene products have more than one SH3 domain, such as the NADPH oxidase subunits (p47, p67), Crk, Nck, Grb2 and Vav (table 2). Very little is known about the function of the SH3 domain. The association of SH3-containing proteins with the cytoskeleton and membrane implies a potential role for the domain in subcellular localization and morphogenesis [ 106]. Sequences of the partial cDNA clone of an SH3-binding protein, 3BP-1, show homology to GAPrelated proteins (rho-GAP), implying a functional association of SH3 proteins with GAP-like proteins and rasGTP-binding proteins [32]. A 10-aa proline-rich sequence, APTMPPPLPP, found in 3BP-1 was defined as an SH3-binding site [ 185]. Mutations in the SH3 domain of the v-src oncogene result in an altered morphology of the mutant-transfomled cells, suggesting that the SH3 domain might be involved in morphological transformation by v-src [236]. The crystal structure of the a-spectrin SH3 domain contains five antiparallel [3-sheets. The 9sheets form a smooth surface which is suggested to be a putative ligand-binding site [ 157]. Signaling Proteins for RPTKs Recently, several signaling proteins have been shown to be physically associated with activated receptor and nonreceptor PTKs. They include phospholipase (PL)C-? [ 132, 149, 237], ras-GTPase-activating protein (GAP) [2, 3, 92]. and phosphatidylinositol-3 kinase (PI3K) [ 13, 39]. GAP, PLC-y and PI3K all contain the SH2 domain. GAP is a 120-kD protein that directly interacts with cellular ras protein and enhances GTPase activity of ras, thereby acting as a negative regulator by returning ras from the active GTP-bound form to the inactive GDP-bound state [ 124, 227, 234]. Molecular cloning of GAP cDNAs shows that GAP contains two SH2 and one SH3 domains at its Nterminal region and a GTPase-activating domain at its Cterminus [227, 234]. GAP becomes tyrosine-phosphory-

70

Liu/Wang

lated by and physically associated with activated EGFR and platelet-defived growth factor (PDGF) receptor (PDGFR) [3, 92, 98]. However, it is still not clear how increased tyrosine-phosphorylation of GAP affects its function. The SH2 domain of GAP has been shown to mediate binding of GAP to specific sequence motifs of the activated EGFR and PDGFR [54]. Tyrosine kinase also induces GAP to associate with two other tyrosine-phosphorylated proteins, p62 and p190 [153, 205, 250]. Surprisingly, p62 cDNA encodes a nucleic-acid-binding protein homologous to a putative hnRNP, GRP33 [250]. GAP binds to tyrosine-phosphorylated p62 through its SH2 domain, p 190 has been shown to be a multidomain protein, homologous to other GAP-activity-containing molecules, such as n-chimaerin, BCR (break point region for c-abl rearrangement in Philadelphia chromosome) oncoprotein, and rho-GAP [205]. p190 could be a potential link for signal transduction from membrane-associated tyrosine kinases to ras-GAP and then to the nucleus [72, 205]. The role of GAP domains in signal transduction becomes more intriguing when two clinically important genes, NF1 (neurofibromatosis type 1 susceptibility gene) and bcr, were shown to have GAP activity [253, 254]. GAP domains are highly conserved in yeast (IRA1, IRA2, CDC42 in Saccharomyces cerevisiae; gap t in Saccharomycespombe) and Drosophila (gap 1) [72]. It is worthwhile mentioning that GAP has a function other than down-regulating ras, namely coupling the K + channel to atrial muscarinic cholinergic receptor [135]. Thus, the role of GAP in signal transduction seems to be more complicated than simply down-regulating ras. PLC-y1 is one of several PLC isoforms which breaks down the phosphatidylinositol-4,5-bisphosphate (PIP2) to diacylglycerol (DAG) and inositol-l,4,5-trisphosphate (IP3) [129, 165, 187]. DAG stimulates protein kinase C (PKC) activity while IP3 increases release of intracellular calcium by binding to IP3 receptor on the endoplasmic reticulum (ER) membrane [9, 150]. The IP3 receptor has multiple transmembrane domains in its C-terminus and may regulate calcium channel opening [ 150]. The enzyme activity of PLC-y1 can be stimulated by PDGF, EGF, and fibroblast growth-factor (FGF) [111, 237, 249]. cDNA clones of PLC-y contain SH2 and SH3 domains [2t8, 220, 221]. PLC-y1 physically associates with activated PDGFR, EGFR and FGF receptor (FGFR) through its SH2 domain [131, 151]. Tyrosine phosphorylation of PLC-y1 is important for its activation and association with activated RPTKs [99, 149, 156, 163]. It seems that PLC-y1 is an important component for signaling by the PDGFR, EGFR, and FGFR. However, PLC-y1 may not SignalTransductionby ProteinTyrosine Kinases

be essential for the mitogenic activity of FGFR or PDGFR since mutants of those RPTKs that are unable to associate with or activate PLC-7 can still cause increased DNA synthesis in response to ligand stimulation [151, 179]. In addition, insulin and IGF-1 receptors can mediate mitogenic responses without phosphorylation of PLC-7, implying that PLC-7 is not essential for the mitogenicity of IR or IGFR [163]. The studies on FGFR association with PLC-7 also suggested that phosphatidylinositol (PI) turnover and calcium influx are not required for mitogenesis [ 151,236]. Two types of PI kinases have been reported. Type I PI3K phosphorylates the inositol ring of PI or PI derivatives (PI-4-P, PI-4,5-P2) at the Y position [245-247]. Type II PI-4 kinase (PI4K), phosphorylates the inositol ring at the 4' position [246, 247]. PI4K involved in the production of PI-4,5-P2 which is the precursor for the well-known second messengers DAG and IP3, as described above. The physiological role of the PI3K products (PI-3-P, PI-3,4-P2, and PI-3,4,5-P3) is not yet clear. The phospholipases that cleave, PI, PI-4-P, and PI-4,5-P2 do not hydrolyze any of the D-3 phosphoinositides, suggesting that the PI-3-P pathway is independent of the well-characterized PI-4-P pathway. Accumulated evidence indicates that PI3K is involved in mitogenic signaling of many oncogenes [60, 61, 93]. Purified PI3K is a heterodimer that consists of 85-kD (p85) and l l0-kD (pll0) polypeptides [26, 154]. Molecular cloning of cDNAs coding for PI3K shows that p85 has no catalytic sequences; instead, it contains SH2 and SH3 domains [53, 171, 213], whereas cDNA coding for p 110 has PI3K catalytic sequences and p85 is not required for the kinase activity ofp110 [78]. Increased PI3K activity is associated with both activated RPTKs like EGFR, PDGFR, IR, Ros, CSF-1R, and c-Kit [4, 51, 82,232], and nonreceptor PTKs, such as Src and Lyn [60, 256]. The association of PI3K with tyrosine phosphoproteins is through the SH2 domain [52, 126]. The structure of the p85 SH2 domain is reported to be similar to those ofv-src and c-abl [17, 172, 238]. Mutations of specific tyrosine-phosphorylation sites on PDGFR abolish its association with PI3K and obviate the growth-factor-induced mitogenesis [54]. PI3K activity is also complexed with p21 ras upon insulin or IGF-1 stimulation, suggesting a link between activated RPTKs (e.g. IR and IGFR) and the p21 ras pathway [212]. PI3K is able to associate with almost every activated RPTK and srclike PTK examined so far, but GAP is not detected in CSF-1R or the c-Kit complex, while PLC-7 fails to bind CSF-IR [25, 231,248]. Whether IR and IGFR bind GAP or PLC-7 remains to be elucidated. These lines of evi-

dence suggest that there are specific signal transduction pathways activated by different RPTKs, but also that these pathways overlap. Src and the related nonreceptor PTKs, such as Fyn and Yes, may directly participate in RPTK signal transduction, since Src, Fyn, and Yes PTKs are physically associated with, and are phosphorylated by the 13-PDGFR [I 12]. PDGF stimulation results in an increase in SRC kinase activity [68]. Src seems also to interplay with IGFR since in Src-transformed cells, tyrosine-phosporylation and kinase activity in IGFR are increased [t09]. However, the biological significance of this interaction remains unclear. Signaling Proteins for Nonreceptor PTKs Many proteins in Rous~sarcoma-virus-transformed cells become tyrosine-phosphorylated and are potential substrates ofpp60 src [73, 186]. A glycoprotein, gp130, was found to be a major substrate of pp60 ~c [74]. Phosphorylation of gpl30 seems to correlate with cell transformation [73, 74]. The molecular identity of gp130 remains unknown. It could be identical to the p130 described by others [186]. Another tyrosine-phosphorylated protein, pll0, is also physically associated with pp60 src [186]. p130 binds to the SH2 domain ofpp60 src, while p110 may associate with its SH3 domain [106]. A 95-kD protein tyrosine-phosporylated by v-src turns out to be the IGFR 13subunit, suggesting a possible interplay between the signaling pathways of the two PTKs [109]. Using cellular extracts containing enriched tyrosine-phosphorylated proteins from v-src-transformed cells as immunogens, Kanner et al. [91] obtained a panel of monoclonal antibodies specific for proteins tyrosine-phosphorylated by pp60 vsrc. Several cDNAs coding for the proteins have been molecularly cloned using the antibodies as screening probes. Among them, an 85-kD polypeptide is a ctyosketetal protein containing the SH3 domain, and is capable of binding to filamentous actin [252]. A 125-kD protein is a new cytoplasmic PTK associated with the focal adhesions in src-transformed cells [p125 F~;K,for focal adhesion kinase; ref. 202]. The tyrosine-phosphorylation of p125 FAK appears to correlate with cell transformation by src and the anchorage-independent growth of the transformed cells [69]. Two other proteins were also found in the src complex. One is the GAP protein, and the other, p62, is now known to be homologous to the hnRNP, GRP33, suggesting that these two proteins are also involved in src signal transduction [ 153, 250]. c-crk, originally found as an oncogene (v-crk) in avian sarcoma virus CT10 [144], codes for a 35-kD protein con-

71

taining one SH2 and two SH3 domains without any recognizable catalytic sequence [184]. Compared with c-crk, verk is fused to the viral gag sequence in the N-terminus and has a large deletion of 100 aa in the C-terminus, including an SH3 domain present in the c-crk product [184]. Tyrosine-phosphorylation of cellular proteins of 62-, 70-, 120-, and 135- to 155-kD is markedly elevated in v-crk-transformed cells. The three major species of 70, 120, and 135-155 kD are specifically associated with the oncoprotein p47gag-crkin vitro [145]. Some cellular tyrosine kinase activities are coimmunoprecipitated with p47gag-erk. The p47 gag'crkcan also complex with p60 v-srcin vitro, and tyrosine-phosphorylation of p60 v-srcis required for their association [ 140]. It was recently shown that the SH2 domains of Crk and PLC-y can protect tyrosinephosphorylated EGFR from dephosphorylation in vitro by protein tyrosine phosphatases [ 188]. It may explain, at least to some extent, why Crk can enhance tyrosine-phosphorylation of cellular proteins. It has been known that phosphorylation of Tyr527 of pp60 src has an inhibitory effect on its tyrosine kinase activity [86]. A distinct cellular protein, Csk (C-terminal src kinase), is molecularly identified as a cytoplasmic tyrosine kinase specifically phosphorylating Tyr527 [159, 168, 197]. The c-src kinase activity is decreased after its phosphorylation by Csk which can also phosphorylate other src family members like p561Y~and p59fyn at tyrosine residues corresponding to the Tyr527 of pp60 c-src [167]. Coexpression of v-crk and c-src causes transformation of rat 3Y1 fibroblasts where c-src kinase activity was elevated. However, v-crk and c-src proteins did not seem to form a stable complex [197, 198]. Csk was shown to be capable of suppressing the transformation induced by coexpression of v-crk and c-src, but unable to reverse the transformed phenotype induced by v-src or c-src527F (Tyr527 mutated to phenylalanine). This study suggests that v-crk may activate c-src kinase in vivo by modulating the phosphorylating state of Tyr527. On the other hand, the oncogenic potential of pp60 c-src can be activated by overexpression of the phosphatase a (PTPasea) in rat embryo fibroblast, and the Tyr527 of c-src is specifically dephosphorylated by the PTPasea [260]. It seems that Crk, Csk and probably certain tyrosine phosphatases are involved in regulation of src PTK activity and its signal transduction. PI3K also appears to be involved in src signal transduction since it has been shown to associate with pp60 v-src [60, 61]. Their association is probably mediated by the SH2 domain of v-src and a tyrosine-phosphorylated sequence of the PI3K [60]. Moreover, the SH3 domain of

72

Liu/Wang

v-src may also be involved in their association [236]. The association of PI3K activity with pp60 v-src is correlated

with its cell-transforming activity. However, several nontransforming src or kinase-inactive src mutants are also capable of associating with the PI3K activity. These results suggest that association of PI3K with src is not sufficient for transformation [60]. Accumulated evidence suggests that the PKC family is also involved in PTK signaling. PKC, a serine/threonine kinase, can be activated either by DAG, a catalytic product of activated PLC-7 as mentioned earlier, or by tumorpromoting phorbol esters, such as 12-O-tetradecanoylphorbol 13-acetate (TPA) [169]. Depletion of PKC by prolonged treatment of chicken embryo fibroblasts with phorbol esters blocked the induction of a transformationrelated gene, 9E3, by v-src and v-fps [217]. The same study also showed that the phosphorylation of a 67-kD PKC substrate was rapidly induced by activation of v-src and v-fps PTKs. By contrast, expression of another gene, Egr-1, induced by activation of v-src PTK, was not affected by either PKC depletion or PKC inhibition [ 182]. These studies indicate that v-src, and perhaps other nonreceptor PTKs (such as fps), may signal through both PKC-dependent and-independent pathways [75, 182, 217]. Ras, an Integration Point in Signaling Pathways o f R P T K s and src-Like P T K s

p21 ras, a well-characterized proto-oncogene with intrinsic GTPase activity, plays a critical role in signal transduction by activated tyrosine kinases [ 134]. Activation of the NGF, EGF, PDGF, insulin receptors and c-kit increases the proportion of the GTP-bound, activated form of p21 ras [63, 201 ]. Studies using a dominant inhibitory mutant of c-Ha-ms, Ha-ras(S17N), and microinjection studies using neutralizing anti-ras antibody have shown that the function of cellular Ras protein is essential for NGF, FGF, CSF-1, and v-src signal transduction [55, 71, 215, 251]. Cross-linking of the T cell receptors and stimulation of mast cells (R6X and MC-9) with interleukins (IL-3, IL-5), and granulocyte/macrophage-colonystimulating factor (GM-CSF) also cause accumulation of GTP-bound p21 ras [45, 48]. Although T cell receptors and those IL receptors have no tyrosine kinase activity, srclike kinases (Lck, Fyn, Lyn) and other tyrosine kinases like ZAP-70 have been shown to be recruited to the activated receptors and are thought to be involved in their signal transduction [27, 34, 77, 102]. Genetic studies on Drosophila eye development have shown that Ras protein is a key signaling element for two tyrosine kinases, sevenSignalTransductionby ProteinTyrosine Kinases

less (ros homolog) and Ellipse [210]. Sos (son of sevenless) is found to be a downstream signal transducer for sevenless but upstream of ras functioning as a guanine-nucleotide-exchanging factor [20, 212]. Studies on the vulval development of Caenorhabditis elegans also demonstrate that Ras (let-60) is required for EGFR (let-23) signal transduction [80]. Ras function is required for transmitting signals from NGF receptors and phorbol ester mitogens through Raf-1, mitogen-activated protein (MAP) kinase, and ribosomal $6 kinase (Rsk) (see below for a more detailed discussion). It is likely that Ras protein represents a converging point in the middle of the signal transduction pathways for RPTKs, nonreceptor PTKs, and probably phorbol-ester-activated PKC [ 134]. Downstream-Signaling Serine/Threonine Kinases Raf-1 is 74-kD protein serine/threonine kinase originally found as a retroviral oncoprotein [118, 183]. It becomes tyrosine-phosphorylated and physically associated with PDGFR upon its activation [155, 156]. Recent reports, however, indicate that Raf can be activated through the IR without accompanying tyrosine-phosphorylation [14, 108], suggesting that Raf-1 may not be a direct substrate of IR tyrosine kinase although it may be involved in the IR signal transduction pathway. The earliest evidence suggesting Raf-I as a downstream signal transducer for ras and src came from microinjection of anti-Ras antibodies [215]. Those neutralizing antibodies blocked the activity of Ras and tyrosine kinase signaling of v-Src and v-Fms but not v-Raf, implying that raflies downstream of ras, src and fms. Phosphorylation and kinase activity of pp74c-raf are increased in cells transformed by src-like oncogenes [I 55]. However, c-Raf lacks SH2 and SH3 domains, so its activation and phosphorylation by src-like PTKs may not take place by direct physical association. Antisense RNA for c-raf-1 and expression of kinase-defective raf-I inhibited serum-induced NIH 3T3 cell proliferation and blocked ras-induced cell transformation [ 107]. This study provided direct evidence that Raf-1 is a signal transducer downstream of Ras. Microinjection of dominant negative rafil RNA into Xenopus embryos blocked mesoderm induction by basic FGF (bFGF), suggesting that Raf-1 mediates bFGF receptor downstream signaling [ 127]. MAP kinases represent another family of serine/ threonine kinases involved in signal transduction by tyrosine kinases and PKC [226]. Though commonly referred to as MAP kinase, the enzyme is also known as extracellular-signal-regulated kinase (Erk) or mitosis-promoting kinase (MPK) [15]. There are several forms of MAP

kinases, p44 mapk (Erkl) and p42 mapk (Erk2) [19, 226]. Growth factors like insulin, EGF, NGF and phorbol esters activate MAP kinase by increasing its tyrosine- and threonine-phosphorylation. Activated MAP kinase then phosphorylates another serine/threonine kinase, Rsk [30, 67, 219]. A fraction of the activated MAP kinase and Rsk enters the nucleus [15, 30]. MAP kinase has been shown to phosphorylate c-Jun and activate its transactivating activity [ 181 ]. MEK1, also known as Erk kinase or MAP kinase kinase (MKK), is a protein tyrosine/threonine kinase which has long been suspected to phosphorylate MAP kinase, and has recently been purified and molecularly cloned [42, 43, 67]. MEK1 expressed in bacteria can phosphorylate Erk at tyrosine and threonine residues [43]. Purified MKK from PC 12 cells was activated by tyrosine/threonine phosphorylation after NGF stimulation [67]. MKK may be a substrate for Raf-1 kinase since it has been shown that Raf-1 can activate purified MKK in vitro. The MAP kinases (Erkl and Erk2) and MKK are constitutively activated in v-raf-transformed fibroblasts [81, 113]. Signaling Proteins with No Catalytic Domains Crk represents the prototype of a class of proteins which have only SH2 and/or SH3 sequences while lacking catalytic domains. In v-crk-transformed cells, tyrosinephosphorylation of a number of proteins is apparently elevated [140, 145]. The Crk oncoprotein may act as an adaptor to bridge a PTK with certain substrates, or it may prevent PTPase from dephosphorylating PTKs, locking them in the active state. The p85 subunit of PI3K contains SH2 and SH3 domains, while the catalytic activity of PI3K resides in p110 [78]. The p85 subunit serves as a regulator of PI3K. It has been documented that many activated RPTKs and src-like kinases associate with and activate the PI3K through binding to the SH2 domain of the p85 subunit [25, 97, 106, 126]. The p85 subunit appears to function as a 'docking' protein to affix the catalytic p110 of PI3K to tyrosine-phosphorylated RPTKs or to the SH2 domains of src-like PTKs. In addition to crk and the p85 subunit of PI3K, more and more SH2-and SH3-containing proteins have been identified recently. The human Nck cDNA codes for a cytoplasmic protein of 377 aa which contains one SH2 and three SH3 domains but has no catalytic sequences [115]. Overexpression of Nck caused transformation of 3Y1 rat fibroblasts and NIH 3T3 ceils [31, 119]. Nck is physically associated with EGFR, PDGFR, pp60 v-srcand cytoplasmic serine/threonine kinases [31, 119]. Phos-

73

phorylation of Nck on serine and tyrosine residues is increased in response to phorbol ester, cAMP, and a variety of receptors including EGFR, PDGFR, NGFR, T cell receptor, B cell receptor and Fc receptor [t 19, 148, 173]. However, total phosphotyrosine levels in the transformed 3Y1 fibroblasts were not elevated [31]. These studies suggest that Nck plays an important role in the control of cell growth. Another putative signaling protein, Shc, was isolated from a cDNA library of Burkitt lymphoma cells [178]. Similarly, Shc cDNA encodes an SH2-containing protein with no identifiable catalytic sequence. The Shc protein also contains an al-collagen-like domain. Shc is tyrosinephosphorylated by and associated with EGFR through its SH2 domain. Shc may also be a cellular substrate for v-src and v-fps [125]. Overexpression of Shc in NIH 3T3 cells resulted in their transformation, and the transformed cells can form tumors in nude mice. These data suggest that Shc may function in src, fps, EGFR and probably other RPTK-signaling pathways. It may play an important role in the mitogenic activities of those PTKs. Unlike v-Crk, Shc-transformed cells do not demonstrate a pronounced increase in tyrosine-phosphorylation of cellular proteins, even though Shc itself is heavily tyrosine-phosporylated by activated EGFR. This suggests that Shc might associate with some signaling proteins different from those complexed with the Crk protein. A new SH2/SH3-containing cDNA, Grb2/Ash was isolated recently which again has no catalytic sequences [ 123, 139]. Human Grb2 (growth-factor-binding protein 2) and rat Ash (abundant src homology) cDNAs encode a protein of about 25 kD with identical aa sequences. This 25-kD protein binds to activated EGFR, PDGFR, but not FGFR, through its SH2 domain. It appears to be a homolog of the sere-5 gene of the C. elegans, which is involved in the let-23 (EGFR-like) and let-60 (ras-like) signaling pathway crucial for the vulval development of C. elegans [33]. Indeed, Grb2/Ash protein seems to be involved in ras mitogenic signaling since coinjecting Grb2 and normal ras can induce DNA synthesis of quiescent REF-52 cells [123]. Consistent with this result, antisense Ash cDNA interferes with 3Y1 cell growth [ 139]. There have been recent reports that Grb2, Shc, Sos and p21 ras can form complexes [22, 50, 62, 117, 192, 193]. Formation of the complex was triggered by activation of tyrosine kinases like EGFR. The complex formation by Grb2, Shc, Sos and p21 ras in response to tyrosine kinase activation provides strong evidence for the link between RPTK and the ras signaling pathway. Genetic studies on Drosophila eye development also demonstrated that Drk

74

Liu/Wang

(downstream-of-receptor kinases) protein, a Drosophila homolog of mammalian Grb2, functions downstream of Sevenless, a Ros-like RPTK [170, 211]. The SH3 domain of Drk was shown to bind to the proline-rich sequence in the tail of Sos, while the SH2 domain of Drk binds to a phosphotyrosine motif on the activated PTK receptor on the membrane [170, 213]. This interaction may help Sos gain access to the membrane-associated Ras and might also enhance the guanine-nucleotide-exchanging activity of Sos [170, 213]. The Vav proto-oncogene product (95 kD) perhaps represents a new class of signaling proteins that contain SH2 and SH3 domains. The ray oncogene was initially isolated from esophageal carcinoma genomic DNA fragments by gene transfer assay [38, 96]. Loss of the N-terminal sequence activates the oncogenicity of the vav protooncogene [95]. The ray proto-oncogene is exclusively expressed in hematopoietic cells. The Vav protein becomes rapidly tyrosine-phosphorylated when T or B cell antigen receptors are activated [23, 24, 130]. In addition, activation of EGFR or PDGFR leads to a marked increase in tyrosine phosphorylation of the p95 ray. Vav also directly associates with activated EGFR through its SH2 domain [130]. These studies suggest that Vav may serve as a messenger molecule for certain RPTKs in the hematopoietic cells. Interestingly, a group of transcription factors involved in interferon (IFN) signal transduction, ISGF-3a (pl 13, p91/84), were found to have SH2 and SH3 domains. These transcription factors have been shown to be tyrosine-phosphorylated in response to IFN-a stimulation [58, 59]. The tyrosine-phosphorylation is necessary for the formation of an active transcription complex. A cytoplasmic tyrosine kinase, tyk2, might be the putative enzyme that is involved in the IFN-a/[3 signaling pathway [233]. Another possible member of this family is HS1, a 75-kD protein strictly expressed in hematopoietic cells [102]. The cDNA product of HS 1 contains a helix-loop domain at its N-terminus and an SH3 domain at its C-terminus. It was recently demonstrated that the HS 1 protein was tyrosine-phosphorylated by and associated with a src-like PTK, Lyn, in activated B cells [257]. HSI may play an important role in signal transduction in hematopoietic cells. With the special structural features mentioned above, ISGF-3a and HS1 may represent a new class of signal transducers that transmit signals from the cell membrane to the nucleus. Even though the SH2-and SH3-containing proteins are favored for signal transduction and protein-protein interactions, a totally different signal transducer, IR substrate-

SignalTransductionby Protein Tyrosine Kinases

1 (IRS-1), may represent a prototype of yet another new family of signaling proteins. The IRS-1 cDNA was originally cloned from a rat liver cDNA library, and codes for a protein component of 185 kD that has been shown to be the major substrate for IR PTK [164, 222]. IRS-1 has neither SH2/SH3 nor catalytic domains. However, it contains over ten tyrosine phosphorylation sites, eight of which are YMXM or YXXM motifs [207, 222]. The tyrosine-phosporylated YXXM and YMXM motifs have been shown to mediate binding of SH2 domains of GAP and PI3K to activated tyrosine kinase receptors [54, 207]. IRS-1 binds to IR and to PI3K in response to insulin stimulation [158,207]. The IRS-1 binding site was mapped to the IR juxtamembrane region [5, 6]. Binding of IRS-1 to the SH2 domain of the PI3K subunit p85 can directly activate PI3K activity in vitro [158]. Thus, IRS-1 may serve as a multivalent bridging protein that connects signaling partners in a complex. It is conceivable that more IRS- l-like proteins will be identified in the near future.

sine-phosphorylation of proteins creates sites for SH2 binding and provides a mechanism for reversible regulation of signal transduction. Although cloning and characterization of the cellular proteins discussed above have provided a wealth of valuable information of PTK signal transduction, many questions remain unanswered. Given the fact that several PTKs (EGFR, PDGFR, pp60 src) can signal through the same downstream molecules (Grb2, Shc, Sos, Ras), how is the specificity of growth signal from each PTK receptor achieved? How does one cell regulate its response to different signals (metabolic versus mitogenic, differentiation versus proliferation)? What is the function of the products of PI3K? Activation of PTKs like EGFR and Src results in tyrosine-phosphorylation of many cellular proteins. What are the identities and functions of those proteins? Further studies on these SH2/SH3-containing proteins and IRSl-like proteins as well as those tyrosine-phosphorylated proteins with unassigned functions will certainly shed more light on the mechanisms for PTK signal transduction.

Concluding Remarks Genetic and biochemical studies of PTKs have allowed us to gradually construct a network of their signal transduction (fig. 1). Extracellular signals from growth factors, such as EGF, PDGF, IGF-1, insulin, CSF-1, HGF, NGF, MGF, and Neu differentiation factor, are first received by transmembrane PTK receptors. Activation of the receptor PTKs upon ligand binding results in autophosphorylation of the receptors themselves and tyrosine-phosphorylation of their cellular substrates. Several cellular targets, such as GAP, PLC-y, PI3K, IRS-1, Shc, Grb2, and Nck, have been found to function downstream of receptor PTKs. Genetic evidence from studies of C. elegans and Drosophila, in conjunction with biological and biochemical evidence from studies of EGFR and PDGFR strongly suggest that the SH2/SH3-containing 'adaptor' proteins, such as Grb2 and Shc, function downstream of receptor PTKs like EGFR, PDGFR, and Sevenless. A guanidine-nucleotide-exchange factor, Sos, residing in a signaling complex with Grb2, Shc, and p21 ras, provides a link between upstream PTKs and the downstream Ras protein. The serine/threonine kinase, Raf-1, may function further downstream and modulate the activity of Thr/Tyr kinases like MKK (MEK). Phosphorylation of MAP kinase (Erk) and Rsk leads to their activation and translocation into the cell nucleus, resulting in altered gene expression. The modular domains like SH2 and SH3 are implicated in mediating the protein-protein interaction. Tyro-

Acknowledgments This work has been supported by NIH grants CA29339 and CA55054and a grant from AaronDiamondFoundation.

75

i e o l e t o ~ o o

J s o e o e

c o • • e l

o o o ~ t o o ~

o o e * * o o o

o~o~

• • o•

* t o o

o~ooo

* t o t •

*o

• ot

oJ

o•

• • oe

••

ma

• o o o

* • • o

*o**

• o o i o o

*a

o•

o•

• • • •oo

• ~*

•oo

• • *o

• • i

• •~

• • • • •

•~

o•

• • • • • •*e

• • • • • • • t •

References 1 Aaronson SA: Growth factors and cancers. Science 254:1146-1153; 1991. 2 Adari H, Lowy DR, Willumsen BM, Der CJ, McCormick F: Guanosine triphosphatase activating protein (GAP) interacts with the p21 ras effector binding domain. Science 240:518-521; 1988. 3 Anderson D, Koch CA, Grea L, Ellis C, Moran MF, Pawson T: Binding of SH2 domains of phospholipase C~ft, GAP, and Src to activated growth factor receptors. Science 250:979-982; 1990. 4 Auger KR, Sertmian LA, Soltoff SP, Libby P, Cantley LC: PDGF-dependent tryrosine phosphorylation stimulates production of novel polyphosphoinositides in intact cells. Cell 57: 167-175;1989. 5 Backer JM, Schroeder GG, Cahill DA, Ullrich & Siddle K, White MF: Cytoplasmic juxtamembrane regions of the insulin receptor: A critical role in ATP binding, endogenous substrate phosphorylation, and insulin-stimulated bioeffects in CHO cells. Biochemistry 30: 6366-6372;1991. 6 Backer JM, Schroeder GG, Kahn CR, Myers MG, Wilden PA, Cahill DA, White MF: Insulin stimulation of phosphatidylinositol 3-kinase activity maps to insulin receptor regions required for endogenous substrate phosphorylation. J Biol Chem 267:1367-1374; 1992. 7 Balduzzi PC, Notter MFD, Morgan HR, Shibuya M: Some biological properties of two new avian sarcoma viruses. J Virol 40:268-275; 1981. 8 Ben-Levy R, Peles E, Goldman-Michael R, Yardan Y: An oncogenic point mutation confers high affinity ligand binding to the neu receptor. J Biol Chem 267:17304-17313; 1992. 9 Berridge M J, Irvine RF: Inositol trisphosphate and cell signaling. Nature 341:197-205; 1989. 10 Besmer PJ, Murphy JE, George PC, Qui F, Betgold PJ, Lederman L, Snyder HW Jr, Brodeur D, Zuckerman EE, Hardy WD: A new acute transforming feline retrovirus and relationship of its oncogene v-k/t with the protein kinase gene family. Nature 320:415-421;1986. 11 Birchmeier C, O'Neill K, Riggs M, Wiglet M: Characterization of ROSl cDNA from a human glioblastoma cell line. Proc Natl Acad Sci USA 87:4799-4803; 1990. 12 Bishop JM: Molecular themes in oncogenesis. Cell 64:235-248;1991. 13 Bjorge JD, Chan TO, Antczak M, Kung HJ, Fujita D J: Activated type 1 phosphatidylinositol kinase is associated with the epidermal growth factor (EGF) receptor following EGF stimulation. Proc Natl Acad Sci USA 87:38163820;1990. 14 Blackshear PJ, Hanpt DM, App H, Rapp UR: Insulin activates the Raf-1 protein kinase. J Biol Chem 265:12131-12134;1990. 15 Blenis J, Growth-regulated signal transduction by the MAP kinases and RSKs. Cancer Cells 3: 445-449;1991.

16 Boni-Schnetzler M, Kaligian A, DelVecchio R, Pilch P: Ligand-dependent intersubunit association within the insulin receptor complex activates its intrinsic kinase activity. J Biol Chem 263:6822-6828;1988. 17 Booker GW, BreezeAL, DowningAK, Panayatou G, Gout I, Waterfield MD, Campbell ID: Structure of an SH2 domain of the p85a subunit of phosphatidylinositol-3-OH kinase. Nature 358:684-687;1992. 18 Bottaro DP, Rubin JS, Faletto DL, Chart AML, Kmiecik TE, Vande Wounde GF, Aaronson SA: Identification of the hepatocyte growth factor receptor as the c-met proto-oncogene product. Science 251:802-804; 1991. 19 Boulton TG, Nye SH, Robbins DJ, Ip NY, Radziejewska E, Morgenbesser SD, Depinho RA, Panayotatos N, Cobb MH, Yancopoulos GD: ERKs: A family of protein-serine/threoninekinases that are activated and tyrosine phosphorylated in response to insulin and NGF. Cell 65: 663-675;1991. 20 Bowtell D, Fn P, Simon M, Senior P: Identification of murine homologues of the Drosophila son of sevenless gene: Potential activators of ras. Proc. Natl Acad Sci USA 89:6511-6515; 1992. 21 Broek D, Toda T, Michaell T, Levin L, Nirchmier C, Zoller M, Powers S, Wigler M: The S. cerevisiae CDC25 gene product regulates the RAS/adenylate cyclase. Cell 48:789-799; 1987. 22 Buday L, Downward J: Epidermal growth factor regulates p21 ras through the formation of a complex of receptor, Grb 1 adapter protein, and Sos nucleotide exchange factor. Cell 73:611620;1993. 23 Bustelo X, Barbacid M: Tyrosine phosphorylation of the vav proto-oncogene product in activated B cells. Science 256:1196-1199;1992. 24 Bustelo X, Ledbetter JA, Barbacid M: Product of ray proto-oncogene defines a new class of tyros•he protein kinase subs•rates. Nature 356: 68-71;1992. 25 Cantley LC, Auger KR, Carpenter C, Duckworth B, Graziani A, Kapeller R, Soltoff S: Oncogenes and signal transduction. Cell 64: 281-302; 1991. 26 Carpenter CL, Duckworth BC, Augers KR, Cohen B, Schaffhausen BS, Cantley LC: Purification and characterization of phosphoinositide 3-kinase from rat liver. J Biol Chem 265: 19704-19711;1990. 27 Chan AC, Iwashima M, Turck CW, Weiss A: ZAP-70: A 70 kd protein tyrosine kinase that associates with the TCR zeta chain. Cell 71: 64%662; 1992. 28 Chert J, Heller D, Pooh B, Kang L, Wang LH: The proto-oncogene c-ros codes for a transmembrane tyros•he protein kinase sharing sequence and structural homology with sevenIess protein of Drosophila melanogaster. Oncogene 6:257-264; 1991.

29 Chen J, Zong CS, Wang LH: Tissue and epithelial all-specific expression of chicken protooncogene c-ros in several organs suggests that it may play roles in their development and mature function. Oncogene 9:in press; 1994. 30 Chert RH, Sarnecki C, Blenis J: Nuclear localization and regulation or erk- and rsk-encoded protein kinases. Mol Cell Biol 12:915-927; 1992. 31 ClaouMM, Fajardo JE, Hanafusa H: The SH2and SH3-containing Nck protein transforms mammalian flbmblasts in the absence of elevated phosphotyrosine levels. Mol Cell BiN 12: 5834-5842;1992. 32 Cicchetti P, Mayer BJ, Thiel G, Baltimore D: Identification of a protein that binds to the SH3 region of Abl and is similar to Bcr and GAP-rho. Science 257:803-806;1992. 33 Clark SG, Stem M J, Horovitz HK: C. elegans cell signaling gene sem-5 encodes a protein with SH2 and SH3 domains. Nature 356:340-344; 1992. 34 Cooke MP, Abraham KM, Forbush KA, Perlmutter RM: Regulation of T cell receptor signaling b y a src family protein-tyrosine kinase (p59fvn). Cell 65:281-291; 1991. 35 Cooper SC, Park M, Blair DG, Trainsky MA, Huebner K, Croce CM, Vande Woude GF: Molecular cloning of a new transforming gene from a chemically transformed human cell line. Nature 311:29-33;1984. 36 Cooper CS, Tempest PR, Beckman PM, Hardin CH, Breakers P: Amplification and overexpress•on of the met gene in spontaneously transformed NIH3T3 mouse fibroblasts. EMBO J 5:2623-2628;1986. 37 Copeland NG, Gilbert D J, Cho BC, Don•van PJ, Jenkins NA, Cosman D, Andersan D, Lyman SD, Williams DE: Mast cell growth factor maps near the Steel locus on mouse chromosome 10 and is deleted in a number of steel alleles. Cell 63:175-183;1990. 38 Coppola J, Bryant S, Koda T, Conway D, Barbacid M: Mechanism of activaton of the vav protooneogene. Cell Growth Differ 2:95-105; 1991. 39 Coughlin SR, Escobedo JA, Williams LT: Role of phosphatidylinositol kinase in PDGF receptor signal transduction. Science 243:11911194;1989. 40 Coulier F, Kumar R, Ernst M, Klein R, MartinZanca D, Barbacid M: Human trk oncogenes activated by point mutation, in-frame deletion, and duplication of the tyros•he kinase domain. Mol Cell Biol 10:4202-4210; 1990. 41 Courier F, Martin-Zanca D, Ernst M, Barbacid M: Mechanism of activation of the human trk oncogene. Mol Cell Biol 9:15-23;1989. 42 Crews CM, Alessandrini A, Erikson ILL: The primary structure of MEK, a protein kinase that phosphorylates the ERK gene product. Science 258:478-480; 1992.

76

Liu/Wang

Signal Transduction by Protein Tyrosine Kinases

43 Crews CM, Erikson RL: Purification of a mufine protein-tyrosine/threonine kinase that phosphorylates and activates the ERK-1 gene product: Relationship to the fission yeast byrl gene product. Proc Natl Acad Sci USA 89: 8205-8209;1992. 44 Davis S, Lu ML, Lo SH, Lin S, Butler JA, Druker BJ, Roberts TM, An Q, Chert LB: Presence of an SH2 domain in the aetin-binding protein tensin. Science 252:712-715; 1991. 45 Downward J, Graves JD, Warne PH, Rayter S, Cantrell DA: Stimulation of p21 ras upon T cell activation. Nature 346:71%723; 1990. 46 Downward J, Yarden Y, Mayes E, Srace G, Totty N, Stockwell P, Ullrich A, Schlessinger J, Waterfield MD: Close similarity of epidermal growth factor receptor and v-erb-B oncogene protein sequences. Nature 307:521-527; 1984. 47 Drubin DG, Mulholland J, Zhu Z, Botstein D: Homology of a yeast actin-binding protein to signal transduction proteins and myosin-I. Nature 343:288-290;1990. 48 Duronio V, Welham MJ, Abraham S, Dryden P, Schrader JW: p21 ras activation via hemopoietin receptors and c-kit requires tyrosine kinase activity but not tyrosine phosphorylation of p21 ~s GTPase-activating protein. Proc Natl Acad Sci USA 89:1587-1591;1992. 49 Ebina Y, Ellis L, Jamagin K, Edery M, Graf L, Clauser E, Ou J, Masiaz F, Kan YW, Goldfine ID, Roth RA, Rutter WJ: The human insulin receptor cDNA: The structural basis for hormone-activated transmembrane signalling. Cell 40:747-758; 1985. 50 Egan SE, Giddings BW, Brooks MW, Buday L, Sizeland AM, Weinherg RA: Association of Sos ras exchange protein with Grb2 is implicated in tyrosine kinase signal transduction and transformation. Nature 363:45-51;1993. 51 Endemann G, Yonezawa K, Roth RA: Phosphatidylinositol kinase of an associated protein is a substrate for the insulin receptor tyrosine kinase. J Binl Chem 265:396-400;1990. 52 Escobedo JA, Kaplan DR, Kavanaugh WM, Turck CW, Williams LT: A phosphatidylinositol-Y kinase binds ot ptatelet-derived growth factor receptor through a specific receptor sequence containing phosphotyrosine. Mol Cell Bio111:1125-1132;1991. 53 Escobedo JA, Navankasattusa S, Kavanaugh WM, Millay D, Fried VA, Williams LT: cDNA cloning of a novel 85 kD protein that has SH2 domains and regulates binding of PI3-kinase to the PDGF 13-receptor. Cell 65:75-82; 1991. 54 Fantl WJ, Escobedo JA, Martin GA, Turck CW, Rosario MD, McCormick F, Williams LT: Distinct phosphotyrosines on a growth factor receptor bind to specific molecules that mediate different signaling pathways. Cell 69: 413-423;1992. 55 Feig LA, Cooper GM: Inhibition of NIH3T3 ceil proliferation by a mutant ms protein with preferential affinity for GDP. Mol Cell BiN 8: 3235-3243; t 988. 56 Flanagan JG, Leder P: The kit ligand: A cell surface molecule altered in steel mutant fibroblasts. Cell 63:185-194; 1990.

57 Frackelton AR Jr, Ross AH, Eisen HN: Characterization and use of monoctonal antibodies for isolation of phosphotyrosine proteins from retrovirus-transformed ceils and growth factorstimulated ceils. Mol Cell Biol 3:1343-1352; 1983. 58 Fu XY: A transcription factor with SH2 and SH3 domains is directly activated by an interferon a-induced cytoplasmic protein tyrosine kinases. Cell 70:323-335;1992. 59 Fu XY, Schindler C, Improta T, Aebersold R, Damell JE: The proteins of ISGF-3, the interferon c~-induced transcriptional activator, define a gene family involved in signal transduction. Proc Natl Aead Sci USA 89:7840-7843; 1992. 60 Fukui Y, Hanafusa H: Phosphatidylinositol kinase activity associates with viral p60 s~c protein. Mol Cell Biol 9:1651-1568;1989. 61 Fukui Y, Kornbluth S, Jong S, Wang L, Hanafusa H: Phosphatidylinositol kinase type I activity associates with various oncogene products. Oncogene Res 4:283-292; 1989. 62 Gale NW, Kaplan S, Lowenstein EJ, Schlessinger J, Bar-SaN D: Grb2 mediates the EGFdependent activation of gnanine nucleotide exchange on ras. Nature 363:88-92; 1993. 63 Gibbs J, Marshall M, Scolnik E, Dixon R, Vogel U: Modulation of guanine nucleotides bound to ras in NIH3T3 cells by oncogenes, growth factors, and the GTPase activating protein (GAP). J Biol Chem 265:20437-20442; 1990. 64 Giordano S, Ponzetto C, Di Renzo MF, Cooper CS, Comoglio PM: Tyrosine kinase receptor indistinguishable from the c-met protein. Nature 339:155-156;1989. 65 Giordano S, Di Renzo MF, Narsirnhan R, Cooper CS, Comoglio PM: Biosynthesis of the protein encoded by the c-met proto-oncogene. Oncogene 4:1383-1388;1989. 66 Glenney JR, Zokas L, Kamps MJ: Monoclonal antibodies to phosphotyrosine. J Immunol Methods 109:277-285; 1988. 67 Gomez N, Cohen P: Dissection of the protein kinase cascade by which nerve growth factor activates MAP kinases. Nature 353:170-173; 1991. 68 Gould KL, Hunter T: Platelet-derived growth factor induces multisite phosphorylation of pp60 ¢-srcand increases its protein tyrosine kinase activity. Mol Ceil Biol 8:3345-3356; 1988. 69 Guan JL, Shalloway D: Regulation of focal adhesion-associated protein tyrosine kinase by both cellular adhesion and oncogcnic transformation. Nature 358:690-692;1992. 70 Haase VH, Snijders AJ, Cooke SM, Teng MN, Kaul D, Beau MML, Bruns GAP, Beraards A: Alternatively spliced ltk mRNA in neurons predicts a receptor with a larger putative extracellular domain. Oncogene 6:2319-2325;1991. 71 Haggag N, Halegoua S, Biola M: Inhibition of growth factor-induced differentiation of PC12 cells by microinjection of antibody to ras p21. Nature 319:680-682;t986. 72 Hall A: Signal transduction through small GTPase- a tale of two GAPs. Cell 69:389-391; 1992.

73 Hamaguchi M, Grandori C, Hanafusa H: Phosphorylation of cellular proteins in Rous sarcoma virus infected cells: Analysis by use of antiphosphotyrosine antibodies. Mol Cell Biol 8: 3035-3042;1988. 74 Hamagnchi M, Matsuda M, Hanafusa H: A glycoprotein in the plasma membrane matrix as ~ major potential substrate of p60v~rc. Mol Cell Biol 10:830-836; 1990. 75 Hart JW, Gaut J, Burstein E, Sadowski H; Young D, Macara IG: The oneogenic protein p60v'src has competence activity but does not activate phosphatidylinositol turnover or protein kinase C in Balb/3T3 cells. Oncogene 5: 467-474; 1990. 76 Hanks SK, Quinn AM, Hunter T: The protein kinase family: Conserved features and deduced phylogeny of the catalytic domains. Science 241:42-52; 1988. 77 Hatakeyama M, Kono T, Kobayashi N, Kawahara A, Levin SD, Permutter RM, Tanignchi T: Interaction of the IL-2 receptor with the srcfamily kinase p56/ck. Identification of novel intermolecular association. Science 252:15231528;1991. 78 Hiles ID, Otsu M, Volinia S, Fry MJ, Gout I, Dhand R, Panyaotou G, Ruia-Larrea F, Thompson A, Totty NF, Hsuan JJ, Courtneidge SA, Parker PJ, Waterfield MJ: PhosphatidylinositoI 3-kinase: Structure and expression of the 110 kd catalytic subunit. Cell 70:419429;1992. 79 Holmes WE, Stiwkowski NIX, Akita RW, Henzel WJ, Lee J, Park JW, Yansura D, Abadi N, Raab H, Lewis GD, Shepard HM, Kuang WJ, Wood WI, Goeddel DV, Vandlen RL: Identification of heregulln, a specific activator of p185 erbB2. Science 256:1205-1210;1992. 80 Horvitz HR, Steruberg PW: Multiple intercellular signalling systems control the development of the Caenorhabditis elegans vulva. Nature 351:535-541;1991. 81 Howes LR, Leevers SJ, Gomez N, Nakilny S, Cohen P, Marshall CJ: Activation of the MAP ldnase pathway by the protein kinase rat'. Cell 71:335-342;1992. 82 Hu P, Margotis B; Skilnik EY, Lammers R, Ullrich A, Schlessinger J: Interaction of phosphatidylinositol 3-kinase-associated p85 with epidermal growth factor and platelet-derived growth factor receptors. Mol Cell Biol 12:981990;1992. 83 Huang EK, Nocka K, Beier DR, Chu TY, Buck J, Lahm HW, Wellner D, Leder P, Besmer P: The hematopoietic growth factor KL is encoded at the SI locus and is the ligand for the c-kit receptor, the gene product of the W locus. Cell 63:225-233;1990. 84 Jong SM, Wang LH: The transforming protein p68gag'r°s of avian sarcoma virus UR2 is a transmembrane protein with the gag portion protruding extracellularly. Oneogene Res 1:721;1987. 85 Jong SM, Zong CS, Dorai T, Wang LH: Transforming properties and substrate specificities of the protein tyrosine kinase oncogenes ros and sre and their recombinants. J Virol 66: 4909-4918; 1992.

77

86 Jove R, Hanafusa H: Cell transformation by the viral src oncogene. Annu Rev Cell Biol 3: 31-56; 1987. 87 Jung G, Saxe CL, Kom ED, Hammer JA III: The heavy chain of Acanthamoeba myosine IB is a fusion of myosin-like and non-myosinlike sequences. Proc Natl Acad Sci USA 84: 6720-6724;1987. 88 Jung G, Saxe CL, Kimmel AR, Hammer JA III: Dictyostelium discoideum contains a gene encoding a myosin I heavy chain. Proc Natl Acad Sci USA 86:6186-6190; 1989, 89 Kadowaki T, Koyasu S, Nishida E, Tobe K, Iznmi T, Takaku F, Sakai H, Yahara I, Masuga M: Tymsine phosphorylation of common and specific sets of cellular proteins rapidly induced by insulin, insulin-like growth factor I, and epidermal growth factor in an intact cell. J Biol Chem 262:7342-7350;1987. 90 Kamps MP, Sefton BM: identification of multiple novel polypeptide substrates of the v-src, v-yes, v-fps, v-ros, and v-erb-B oncogenic tyrosine protein kinases utilizing antisera against phosphotyrosine. Oncogene 2:305315;1988. 91 Kanner SB, Reynolds AB, Vines RR, Parsons JT: Monoclonal antibodies to individual tyrosine~phosphorylated protein substrates of oncogene-encoded tyrosine kinases. Proc Natl Acad Sci USA 87:3328-3332;1990. 92 Kaplan DR, Morrison DK, Wong G, McCormick F, Williams LT: PDGF [3-receptor stimulates tyrosine phosphorylation of GAP and association of GAP with a signaling complex. Ceil 61:125-133;1990. 93 Kaplan DR, Whitman M, Schauffhansen B, Pallas DC, White M, Cantley L, Roberts TM: Common elements in growth factor stimulation and oncogenic transformation: 85 Kd phosphoprotein and phosphatidylinositol kinase activity. Cell 50:1021-1029; 1987. 94 Katan M, Parker P J: Oncogenes and celt control. Nature 332:203; 1988. 95 Katzav S, Cleveland JL, Heslop HE, Pulido D: Loss of the aminoterminal helix-loop-helix domain of the ray protc-oncogene activates its transforming potential. Mol Ceil Biol 11: 1912-1920;1991. 96 Katzav S, Martin-Zanca D, Barbacid M: va~. a novel human oncogene derived from a locus ubiquitously expressed in hematopoietic cells. EMBO J 8:2283-2290; 1989. 97 Kavanaugh WM, Klippel A, Escobedo JA, Williams LT: Modification of the 85-kilodalton subunit of phosphatidyt-3 kinase in platelet-derived growth factor-stimulated cells. Mol Cell BiN 12:3415-3424;1992. 98 Kazlauskas A, Ellis C, Pawson T, Cooper JA: Binding of GAP to activated PDGF receptors. Science 247:1578-1581; 1990. 99 Kim HK, Kim JW, Zilberstein A, Margolis B, Kim JG, Schlessinger J, Rhee SG: PDGF stimulation of inositol phospholipid hydrolysis requires PLC-gammal phosphorylation on tyrosine residues 783 and 1254. Cell 65: 435--441;1991. 100 King CR, Kraus MH, Aaronson SA: Amplification of a novel v-erbB-related gene in a human mammary carcinoma. Science 229: 974-976;1985.

101 Kitamura D, Haneko H, Miyagoe Y, Ariyasu T, Watanabe T: Isolation and characterization of a novel human gene expressed specifically in the cells of hematopoietic lineage. Nucleic Acids Res 17:9367-9379; 1989. 102 Klansner RD, Samelson LE: T cell antigen receptor activation pathway: The tyrosine kinase connection. Cell 64:875-878;1991. 103 Klein R, Conway D, Parada LF, Barbacid M: The trkB protein tyrosine kinase gene codes for a second neurogenic receptor that lacks the catalytic kinase domain. Cell 61:647-656; 1990. 104 Klein R, Jung S, Nanduri V, O'Rourke E, Barbacid M: The trk proto-oncogene encodes a receptor for nerve growth factor. Cell 65: 189-197;1991. 105 Klein R, Nanduri V, Jung SA, Lamballe F, Tapley P, Bryant S, Corson-Cardo C, Jones KR, Reichardt LF, Barbacid M: The trkB tyrosine kinase is a receptor for brain-derived neurotrophic factor and neurotrophin-3. Cell 66:395-403;1991. 106 Koch CA, Anderson D, Moran MF, Ellis C, Pawson T: SH2 and SH3 domains: Elements that control interactions of cytoplasmic signaling proteins. Science 252:668-674; 1991. 107 Kolch W, Heidecker G, Lloyd P, Rapp U: Raf-1 protein kinase is required for growth of induced NIH/3T3 cells. Nature 349:426-428; 1991. 108 Kovacina KS, Yonezawa K, Brantigan DL, Tonks NK, Rapp UR, Roth RA: Insulin activates the kinase activity of the Raf-1 protooncogene by increasing its serine phosphrylation. J BiN Chem 265:12115-12118;1990. 109 Kozma LM, Weber MJ: Constitutive phosphorytation of the receptor for insulinlike growth factor I in ceils transformed by the src oncogene. Mol Cell Biot 10:3626-3634; 1990. 110 Kraus MH, Issing W, Miki T, Popesco NC, Aaronson SA: Isolation and characterization of ERBB3, a third member of the ERBB/epidermal growth factor receptor family: Evidence for overexpresison in a subset of human mammary tumors. Proc Natl Acad Sci USA 86:9193-9197;1989. 111 Kumjian DA, Wahl MI, Rhee SG, Daniel TO: Platelet-derived growth factor binding promotes physical association of PDGF receptor with phospholipase C. Proc Natl Acad Sci USA 86:8232-8239;1989. 112 Kypta RM, Goldberg Y, Ulug E, Cortneidge SA: Association between PDGF receptor and members of the sre family of tyrosine kinases. Cell 62:481-492; 1990. 113 Kyriakis JM; App H, Zhang XF, Banerjee P, Brautigan DL, Rapp UL, Avruch J: Raf-1 activates MAP kinase-kinase. Nature 358: 417-421;i992. 114 Lamballe F, Klein R, Barbacid M: trkC, a new member of the trk family of tyrosine protein kinases, is a receptor for neurotmphin-3. Cell 66:967-979;1991. 115 Lehmann JM, Reithmuller G, Johnson JP: Nck, a melanoma eDNA encoding a cytoplasmic protein consists of the Src homology units SH2 and SH3. Nucleic Acid Res 18:1048; 1990.

116 Leto TL, Lomax KJ, Volpp BD, Nunoi H, Sechler JMG, NauseefWM, Clark RA, Gallin JL, Malech HL: Cloning of a 67-kD neutrophil oxidase factor with similarity to a noncatalytic region of p60c'srq Science 248:727730;1990. 117 Li N, Batzer A, Daly R, Yajnik V, Skolnik E, Chardin P, Bar-Sagi D, Margolis B, Schlessinger J: Guanine-nucleotide-releasing factor hSosl binds to Grb2 and links receptor tyrosine kinases to ras signaling. Nature 363:8588;t993. 118 Li P, Wood K, Mamon H, Haser W, Roberts T: Raf-1: A kinase currently without a cause but not lacking effects. Cell 64:479-482; 1991. 119 Li W, Hu P, Skolnik EY, Ullrich A, Schlessinger J: The SH2-and SH3-containing Nck protein is oncogenic and a common target for phosphorylation by different surface receptors. Mol Cell Biol 12:5824-5833;1992. 120 Liu D, Rutter WJ, Wang LH: Enhancement of transfbrming potential of human insulinlike growth factor I receptor by N-terminal truncation and fusion to avian sarcoma virus UR2 gag sequence. J Virol 66:374-385; 1992. 121 Liu D, Rutter WJ, Wang LH: Modulating effects of extracellular sequence of human insulinlike growth factor I receptor on its transforming and tumorigenic potential. J Viro167:9-18;1993. 122 Liu D, Zong CS, Wang LH: Distinctive effects of carboxyl terminal sequence of insulinlike growth factor I receptor on its signaling functions. J Viro167:6835-6840; 1993. 123 Lowenstein EJ, Daly RJ, Batzer AG, Li W, Margolis B, Lanlmers R, Ullrich A, Skolnik EY, Bar-Sagi D, Schlessinger J: The SH2 and SH3 domain-containing protein GRB2 links receptor tyrosine kinases to ras signaling. Cell 70:431-442; 1992. 124 McCormick F: ras GTPase activating protein: Signal transmitter and signal terminator. Cell 56:5-8; 1989. 125 McGlade JA, Cheng A, Pelicc~ G, Pelicci PC, Pawson T: Shc proteins are phosphorylated and regulated by the v-Src and v-Fps proteintyxosine kinases. Proc Natl Aead Sci USA 89: 8869-8873;1992. 126 McGlade J, Ellis C, Reedijk M, Anderson D, Mbamalu G, Reith AD, Panayotou G, End P, Bernstein A, Kazlauskas A, Waterfield MD, Pawson T: SH2 domains of the p85a subunit of phosphatidylinositol 3-kinase regulate binding to growth factor receptors. Mol Cell Biol 12:991-997;1992. 127 MacNicol AM, Muslin AJ, Williams LT: Rail kinase is essential for early Xenopus development and mediates the induction of mesoderm by FGF. Cell 73:571-583; 1993. 128 Maegawa H, MeClain DA, Freidenberg G, Olefsky JM, Napier M, Lipair T, Dull TJ, Lee J, Ullrich A: Properties of a human insulin receptor with a COOH-terminal truncation. II: Truncated receptors have normal kinase activity but are defective in signaling metabolic effects. J Biol Chem 263:8912-8917; 1988.

78

Liu/Wang

Signal Transduction by Protein Tyrosine Kinases

129 Majerus PW, Connolly TM, Deckmyn H, Ross TS, Bross TE, Ishii H, Bansal VS, Wilson DB: The metabolism of phosphoinositide-derived messenger molecules. Science 234:1519-1526;1986. 130 Margolis B, Hu H, Katzav S, Li W, Oliver JM, Ullrich A, Weiss A, Schlessinger J: Tyrosine phosphorylation of vav proto-oncogene product containing SH2 domain and transcription factor motifs. Nature 356:71-74; 1992. 131 Margolis B, Li N, Koch A, Mohamaddi M, Hurwitz DR, Zilberstein A, Ullrich A, Pawson T, Schlessinger J: The tyrosine phosphorylated carboxyterminus of the EGF receptor is a binding site of GAP and PLC-~/. EMBO J 9:4375-4380;1990. 132 Margolis B, Rhee SG, Felder S, Metric M, Lyall R, Levitzki A, Ullrich A, Zilberstein A, Schlessinger J: EGF induces tyrosine phosphorylation of phospholipase C-II: A potential mechanism for EGF signalling. Cell 57: 1101-1107;1989. 133 Margotis B, Silvennoinen O, Comogtio F, Roonprapunt C, Skolnik E, Ullrich A, Schlessinger J: High efficiency expression/cloningof epidermal growth factor receptor binding proteins with src homology 2 domains. Proc Natl Acad Sci USA 89:8894-8898;1992. 134 Marshall CJ: How does p21 ras transform cells? Trends Genet 7:91-95;1991. 135 Martin GA, Yantani A, Clark R, Couroy L, Polakis P, Brown AM, McCormick F: GAP domains responsible for ras p21-dependent inhibition of muscarinic atrial K + channel currents. Science 255:192-194; 1992. 136 Martin-Zanca D, Hughes SH, Barbacid M: A human oncogene formed by the fusion of truncated tropomyosin and protein tyrosine kinase sequences. Nature 319:743-748; 1986. 137 Martin-Zanca D, Oskam R, Mitra G, Copeland T, Barbacid M: Molecular and biochemical characterization of the human trk protooncogene. Mol Cell Biol 9:24-33; 1989. 138 Massoglia S, Gray A, Dull TJ, Munemitsu S, Kung H J, Schlessinger J, Ullrich A: Epidermal growth factor receptor cytoplasmic domain mutations trigger ligand-independent transformation. Mol Cell Biol 10:3048-3055; 1992. 139 Matouka K, Shibata M, Yamakawa A, Takenawa T: Cloning of ASH, a ubiquitous protein composed of one src homology region 2 and two SH3 domains, From human and rat cDNA libraries. Proc Natl Acad Sci USA 89: 9015-9019;1992. 140 Matsuda M, Mayer BJ, Fukui Y, Hanafusa H: Binding of transforming protein, p47gag-crk to a broad range of phosphotyrosine containing proteins. Science 248:1537-1539; 1990. 141 Matsushime H, Shibuya M: Tissue specific expression of rat c-ros-1 gene and partial structural similarity of its predicted products with sev protein o f Drosophila melanogaster. J Viro164:2117-2125;1990.

142 Matsushime H, Wang LH, Shibuya M: Human c-ros-1 gene homologous to the v-ms sequence of UR2 sarcoma virus encodes a transmembrane receptorlike molecule. Mol Cell Biol 6: 3000-3004; 1986. 143 Matthews W, Jordan CT, Wiegand GW, Pardoll D, Lemischka IR, A receptor tyrosine kinase specific to hematopoietic stem and progenitor cell-enriched populations. Cell 65: 1143-1152;1991. 144 Mayer BJ, Hamaguchi M, Hanafusa H: A novel viral oncogene with structural similarity to phospholipase C. Nature 332:272-275; 1988. 145 Mayer BJ, Hanafusa H: Association of the vcrk oncogene product with phosphotyrosinecontaining proteins and protein tyrosine kinase activity. Proc Natl Acad Sci USA 87: 2638-2642;1990. 146 Mayer BJ, Jackson PK, Baltimore D: The noncatalytic src homology region-2 segment of abl tyrosine kinase binds to tyrosine-phosphorylated cellular proteins with high affinity. Proc Natl Acad Sci USA 88:627-631; 1991. 147 Mayer BJ, Jackson PK, Van Etten RA, Baltimore D: Point mutations in the abl SI-I2 domain coordinately impair phosphotyrosine binding in vitro and transformation activity in vivo. Mol Cell Biol 12:609-618; 1992. 148 Meisenhelder J, Hunter T: The SH2- and SH3-containing protein Nck is recognized by certain anti-phospholipase C q l monoclonal antibodies, and its phosphorylation on tyrosine is stimulated by PDGF and EGF treatment. Mol Cell Biot 12:5843-5856;1992. 149 Meisenhelder J, Sub PG, Rhee SG, Hunter T: Phospholipase C-,/ is a substrate for the PDGF and EGF receptor protein-tyrosine kinases in vivo and in vitro. Cell 57:1109-1122; 1989. 150 Mignery GA, SudhofTC: The ligand binding site and transduction mechanism in the inositol-l,4,5-trisphosphate receptor. EMBO J 9: 3893-3898;1990. 151 Mohammadi M, Dionne CA, Li W, Li N, Spiyak T, Honegger AM, Jaye M, Schlessinger J: Point mutation in FGF receptor eliminates phosphatidylinositol hydrolysis without affecting mitogenesis. Nature 358:681-684; 1992. 152 Mondino A, Giordano S, Comoglio PM: Defective posttranslational processing activates tyrosine kinase encoded by the MET protooncogene (hepatocyte growth factor receptor). Mol Cell Biol 11:6084-6092; 1991. 153 Moran MF, Koch CA, Anderson D, Ellis C, England L, Martin GS, Pawson T: src homology region 2 domains direct protein-protein interactions in signal transduction. Proc Natl Acad Sci USA 87:8622-8626; 1990. 154 Morgan SJ, Smith AD, Parker PJ: Purification and characterization of bovine brain type I phosphatidylinositol kinase. Eur J Biochem 191:761-767;1990.

155 Morrison DK, Kaplan DR, Esscobedo JA, Rapp UR, Roberts TM, Williams LT: Direct activation of the serine/threonine kinase activity of Raf-1 through tyrosine phosphorylation by the PDGF [~-receptor. Cell 58:649657;1989. 156 Morrison DK, Kaplan DR, Rhee SG, Williams LT: PDGF-dependent association of PLC-gamma with the PDGF receptor signaling complex. Mol Cell Biol 10:2359-2366; 1990. 157 Musacchio A, Noble M, Paubtit R, Wierenga R, Saraste M: Crystal structure of a Srchomology 3 (SH3) domain. Nature 359:851855;1992. 158 Myers MG, Backer JM Sun XJ, Shoelson SE, Hu P, Schlessinger J, Yoakim M, Schaffhausen B, White MF: IRS-1 activates phosphatidylinositol 3'-kinase by associating with src homology 2 domain of p85. Proc Natl Acad Sci USA 89:10350-10354;1992. 159 Nada S, Okada M, MacAnley A, Cooper JAm Nakagawa H: Cloning of a complementary DNA for a protein-tyrosine kinase that specifically phosphorylates a negative regulatory site of p60c-sty.Nature 351:69-72; 1991. 160 Neckameyer WS, Shibuya M, t-Isu MT, Wang LM: Proto-oncogene c-ros codes for a molecule with structural features common to those of growth factor receptors and displays tissuespecific and developmentally regulated expression. Mol Cell Biol 6:1478-1486; 1986. 161 Neckameyer WS, Wang LH: Molecular cloning and characterization of avian sarcoma virus UR2 and comparison of its transforming sequence with those of other avian sarcoma viruses. J Viro150:914-921;1984. 162 Neckameyer WS, Wang LH: Nueleotide sequence of avian sarcoma virus UR2 and comparison of its transforming gene with other members of the tyrosine protein kinase oncogene family. J Viro153:879-884; 1985. 163 Nishibe S, Wahl MI, Wedegaertner PB, Kim JJ, Rhee SG, Carpenter G: Selectivity of phospholipase C phosphorylation by the epidermal growth factor receptor, the insulin receptor, and their cytoplasmic domains. Proc Natl Acad Sci USA 87:424-428; 1990. 164 Nishiyama M, Wands JR: Cloning and increased expression of an insulin receptor substrate-l-like gene in human hepatocellular carcinoma, Biochem Biophys Res Commun 183:280-285;1992. 165 Nishizuka Y: Turnover of inositol phospholipids and signal transduction. Science 225: 1365-1370;1984. 166 O'Bryan JP, Frye RA, Cogswell PC, Neubauer A, Kitch B, Prokop C, Espinosa R, Mean MM, Earp HS, Liu ET: axl, a transforming gene isolated from primary human myeloid leukemia cells, encodes a novel receptor tyrosine kinase. Mol Cell Biol 11: 5016-5031;1991. 167 Okada M, Nada S, Yamanashi Y, Yamamoto T, Nakagawa H: CSK: A protein tyrosine kinase involved in regulation of src family kinases. J Biol Chem 266:24249-24252; 1991.

79

168 Okada M, Nakagawa H: A protein tyrosine kinase involved in regulation of pp60c-src. J Biol Chem 264:20886-20893;1989. 169 Ogita K, Koide H, Kikkawa U, Kishimoto A, Nishizuka J: The heterogeneity of protein kinase C in signal transduction cascade; in Nishizuka J, et al. (eds): The Biology and Medicine of Signal Transduction. New York, Raven, 218-223;1990. 170 Oliver JP, Raabe T, Henkemeyer M, Dickson B, Mbamalu G, Margolis B, Schlessinger J, Hafen E, Pawson T: A Drosophila SI-I2-SH3 adaptor protein implicated in coupling the Sevenless tyrosine kinase to an activator of Ras guanine nucleotide exchange, Sos. Cell 73:179-191;1993. 171 Osu M, Hiles I, Gout I, Fry MJ, Ruiz-Larrea F, Panayotou G, Thompson A, Dhand R, Hsuan J, Totty N, Smith AD, Morgan SJ, Courtneidge SA, Parker PJ, Waterfield MD: Characterization of two 85 kD proteins that associate with receptor tyrosine kinases, middle-T/pp60 v'src complexes, and PI3-kinase. Cell 65:91-104;1991. 172 Overduin M, Rios CB, Mayer BJ, Baltimore D, Cowbum D: Three-dimensional solution structure of the src homology 2 domain of cabt. Cell 70:697-704;1992. 173 Park D, Rhee SG: Phosphorylation of Nck in response to a variety of receptors, phorbol myristate acetate, and cyclic AMP. Mol Cell Bio112:5816-5823;1992. 174 Park M, Dean M, Cooper CS, Schmidt M, O'Brien SJ, Blair DG, Vande Woude GF: Mechanisms of met oncogene activation. Cell 45:895-904;1986. 175 Pasquale EB, Singer SJ: Identification of a developmentally regulated protein-tyrosine kinase by using anti-phosphotyrosine antibodies to screen a eDNA library. Proc Natl Acad Sci USA 86:5449-5453;1989. I76 Pawson T, Gish GD: SH2 and SH3 domains: From structure to function. Cell 71:359-362; 1992. 177 Peles E, Bacus SS, Koski RA, Lu HS, Wen D, Ogden SG, Ben-Levy R, Yarden Y: Isolation of the Neu/HER2 stimulatory ligand: A 44kd glycoprotein that induces differentiation of mammary tumor cells. Cell 69:205-216; 1992. 178 Pelicci G, Lanfrancone L, Grignani F, McGlade J, Cavallo F, Fomi G, Nicoletti I, Grignani F, Pawson T, Pelicci PG: A novel transforming protein (SHC) with an SH2 domain is implicated in mitogenic signal transduction. Cell 70:93-104; 1992. t79 Peters KG, Marie J, Wilson E, Ires HE, Escobedo J, Rosario MD, Mirda D, Williams LT: Point mutation of an FGF receptor abolishes phosphatidylinositol turnover and Ca2+ flux but not mitogenesis. Nature 358:678-681; 1992. 180 Pooh BD, Dixon D, Ellis L, Roth RA, Rutter W J, Wang LH: Molecular basis for the activation of the tumorigenic potential of Gag-insulin receptor chimeras. Proc Natl Acad Sci USA 88:877-881; 1991.

181 Pulverer BJ, Kyriakis JM, Avmch J, Nikolakaki E, Woodgett JR: Phosphorylation of cjun mediated by MAP kinases. Nature 353: 670-674; 1991. 182 Qureshi SA, Joseph CK, Rim M, Maroney A, Foster DA: v-Src activates both protein kinase C-dependent and independent pathways in murine fibroblasts. Oncogene 6:995-999; 1991. 183 Rapp UR, Heidecker G, Huleihel M, Cleveland JL, Choi WC, Pawson T, Ihte JN, Anderson WB: raffamily serine/threonine protein kinases in mitogen signal transduction. Cold Spring Harbor Syrup Qant Biol 53:173-184; 1988. 184 Reichman CT, Mayer BJ, Keshav S, Hanafusa H: The product of the celltdar crkgene consists primarily of SH2 and SH3 regions. Cell Growth Differ 3:451-460; 1992. 185 Ren RB, Mayer B, Ciccetti P, Baltimore D: Identification of a ten-amino acid prolinerich SH3-binding site. Science 259:11571161;1993. 186 Reynolds AB, Kanner SB, Wang HCR, Parsons JT: Stable association of activated pp60~'rwith two tyrosine phosphorylated cellular proteins. Mol Cell Biol 9:3951-3958; I989. 187 Rhee SG, Suh PG, Ryu SH, Lee SY: Studies of inositol phospholipid-specific phospholipase C. Science 244:546-550; 1989. 188 Riotin D, Margolis B, Mohammadi M, Daly R J, Daum G, Li N, Fisher EH, Burgess WH, Ullrich A, Schlessinger J: SH2 domains prevent tyrosine dephosphorylation of the EGF receptor: Identification of Tyr992 as the highaffinity binding site for SH2 domains ofphospholipase C7. EMBO J 11:559-567; 1992. t89 Rodaway AR, Steinberg MJE, Bentley DL: Similarity among membrane proteins, Nature 342:624;1989. 190 Ross AH, Baltimore D, Eisen HN: Phosphotyrosine-containingproteins isolated by affinity chromatography with antibodies to a synthetic hapten. Nature 294:654-656; 1981. 191 Roussel MF, Rettenmier CW, Look AT, Sheer CJ: Ceil surface expression of v-finscoded glycoproteins is required for transformation. Mol Cell BiN 4:1999-2009; 1984. 192 Rozakis-Adcock M, Femley R, Wade J, Pawson T, Bowtell D: The SH2 and SH3 domains of mammalian Grb2 couple the EGF receptor to the ras activator mSosl. Nature 363:8385;1993. 193 Rozakis-Adcock M, McGlade M, Mbamalu G, Pelicci G, Daly R, Li W, Batzer A, Pelicci PG, Schlessinger J, Pawson T: Association of the She and Grb2/Sem-5 SH2-containing proteins is implicated in activation of the Ras pathway by tyrosine kmase. Nature 360:689692;1992. 194 RuffP, Speicher DW, Husain-Chishti A: Molecular identification of a major patmitoylated erythrocyte membrane protein containing the src homology 3 motif. Proc Natl Acad Sci USA 88:6595-6599;199I.

195 Russell RB, Breed J, Barton GJ: Conservation analysis and structure prediction of the SH2 family of phosphotyrosine binding domains. FEBS Left 304:15-20; 1992. 196 Ruta M, Burgess W, Givol D, Epstein J, Neiget N, Kaplow J, Crumley G, Dionne C, Jaye M, Schlessinger J: Receptor for acidic fibroblast growth factor is related to the tyrosine kinase encoded by t h e f m s like gene (fig). Proc Natl Acad Sci USA 86:8722-8726; 1989. 197 Sabe H, Knudsen B, Okada M, Nada S, Nakagawa H, Hanafusa H: Molecular cloning and expression of chicken C-terminus src kinase: Lack of stable association with c-src protein. Proc Natl Acad Sci USA 89:2190-2194; 1992. 198 Sabe H. Okada M, Nakagawa H, Hanafusa H: Activation of c-src in cells bearing v-crk and its suppression by csk. Mol Cell Biol 12:47064713;1992. 199 Sacca R, Stanley ER, Sherr CJ, Rettenmier CW: Specific binding of the mononuclear phagocyte colony-stimulating actor CSF-1 to the product of the v-fms oncogene. Proc Natl Acad Sci USA 83:3331-3335;1986. 200 Sadowski I, Stone JC, Pawson T: A noncatalytic domain among cytoplastic protein tyrosine kinases modifies the kinase function and transforming activity of Fujinami sarcoma virus P13Ogag'fps Mol Cell Biol 6:4396-4408; 1986. 201 Sartoh T, Endo M, Nakafuku M, Nakamura S, Kaziro Y: Platelet-derived growth factor stimulates formation of active p21 ras, GTP compelx in Swiss mouse 3T3 cells. Proc Natl Aead Sci USA 87:5993-5997; 1990. 202 Schaller MD, Borgman CA, Cobb BS, Vines RR, Reynolds AB, Parsons JT: pp125 Fm¢, a structurally distinctive protein-tyrosine kinase associated with focal adhesions. Proc Natl Acad Sci USA 89:5192-5196;1992. 203 Schechter AL, Stem DF, Vaidyanathan L, Decker SJ, Drebin JA, Greene MI, Weinberg RA: The neu oncogene: an erbB-related gene encoding a 185,000-Mr tumor antigen. Nature 312:513-516;1985. 204 Schlessinger J: Signal transduction by allosteric receptor oligomerization. Trends Biochem Sci 13:443-447; 1988. 205 Settleman J, Narasimhan V, Foster LC, Weinberg RA: Molecular cloning of cDNAs encoding the GAP-associated protein p190: Implications for a signaling pathway from ras to the nucleus. Cell 69:539-549; 1992. 206 Shen SH, Bastien L, Posner BI, Chretien P: A protein tyrosine phosphatase with sequence similarity to the SH2 domain of the protein tyrosine kinases. Nature 352:736-739; 1991. 207 Shoelson SE, Chatterjee S, Chaudhuri M, White MF: YMXM motifs of IRS-1 define substrate specificity of the insulin receptor kinase. Proc Natl Acad Sci USA 89:20272031;1992. 208 Shier P, Watt VM: Primary structure of a putative receptor for a ligand of the insulin family. J Biol Chem 264:14605-14608; 1989.

80

Liu/Wang

Signal Transduction by Protein Tyrosine Kinases

209 Shu HKG, Pelly RJ, Kung HJ: Dissecting the activating mutations in v-erbB or avian erythroblastosis virus strain R. J Virol 65: 6173-6180;1991. 210 Simon MA, Bowteil D, Dodson GS, Laverty TR, Rubin GM: Rasl and a putative guanine nucleotide exchange factor perform crucial steps in signaling by the sevenless protein tyrosine kinase. Ceil 67:701-716;1991. 211 Simon MA, Dodson GS, Rubin GM: An SH3-SH2-SH3 protein in required for p21 rasl activation and binds to sevenless and Sos proteins in vitro. Cell 73:169-177; 1993. 212 Sjolander A, Yamamoto K, Huber BE, Lapetina EG: Association of p21 ras with phosphatidylinositol 3-kinase. Proc Natl Acad Sci USA 88:7908-7912;1991. 213 Skoinik EY, Margolis B, Mohammadi M, Lowenstein E, Fischer R, Drepps A, Ullrich A, Schlessinger J: Cloning of P 13 kinase-associated p85 utilizing a novel method for expression/cloning of target proteins for receptor tyrosine kinases. Cell 65:83-90;1991. 214 Smith DR, Vogt PK, Hayman MJ: The v-sea oncogene of the avian retrovirus S 13: Another member of the protein tyrosine kinase gene family. Proc Natl Acad Sci USA 86:52915296;1989. 215 Smith MR, Degudicibus SJ, Stacey DW: Requirement for c-ras proteins during viral oncogene transformation. Nature 320:540-543; 1986. 216 Sonnenberg E, Godecke A, Walter B, Bladt F, Birchmeier C: Transient and locally restricted expression of the rosl protooncogene during mouse development. EMBO J 10:3693-3702; 1991. 217 Spangter R, Joseph C, Qureshi SA, Berg KL, Foster DA: Evidence that src a n d v-fps gene products use a protein kinase C-mediated pathway to induce expression of a transformation-related gene. Proc Natl Acad Sci USA 86:7017-7021;1989. 218 Stahl ML, Ferenz CR Kelleher KL, Kriz RW, Knopf JL: Sequence similarity of phopholipase C with the non-catalytic region of src. Nature 332:269-272; 1988, 219 Sturgill TW, Ray LB, Erikson E, Maller JL: Insulin-stimulated MAP-2 kinase phosphorylates and activates ribosomal protein S6 kinase II. Nature 334:715-718; 1988. 220 Suh PS, Ryu SH, Moon KH, Sub HW, Rhee SG: Inositol phospholipid-specific phospholipase C: Complete cDNA and protein sequences and sequence homology to tyrosine kinase-related oncogene products. Proc Nail Acad Sci USA 85:5419-5423;1988. 221 Sub P, Ryu SH, Moon KH, Suh HW, Rhee SG: Cloning and sequence of multiple forms of phospholipase C. Cell 54:161 - 169; 1988. 222 Sun X J, Rothenberg P, Kahn CR, Backer JM, Araki E, Wilden PA, Cahill DA, Goldstein BJ, White MF: Structure of the insulin receptor substrate IRS-1 defines a unique signal transduction protein. Nature 352:73-77; 1991.

223 Takahashi M, Cooper GM: ret transforming gene encodes a fusion protein homologous to tyrosine kinases. Mol Cell Biol 7:1378-1385; 1987. 224 Tempest PR, Cooper CS, Major GN: The activated human m e t gene encodes a protein tyrosine kinase. FEBS Lett 209:357-360; 1986. 225 Tessarollo L, Nagarajan L, Parada L: c-ros: The vertebrate homolog of the sevenless tyrosine kinase receptor is tightly regulated during organogenesis in mouse embryonic development. Development 115:11-20; 1992. 226 Thomas G: MAP kinase by any other name smells just as sweet. Cell 68:3.6; 1992. 227 Trahey M, Wang (3, Halenbeck R, Rubinfeld B, Martin GA, Ladner M, Long CM, Crosier WJ, Watt K, Koths K, McCormick F: Molecular cloning of two types of GAP complementary DNA from human placenta. Science 242: 1697-1700;1988. 228 Truehart J, Boeke JD, Fink GR: Two genes required for cell fusion during yeast conjugation: Evidence for a pheromone-induced surface protein. Mol Cell Biol 7:2316-2328; 1987. 229 Ullrich A, Bell J, Chert EY, Herrera R, Petruzzelli LM, Dull T J, Gray A, Coussens L, Liao YC, Tsubokawa M, Mason A, Seeburg PH, Gnmfeld C, Rosen OM, Ramachandran J: Human insulin receptor and its relationship to the tyorsine kinase family of oncogenes. Nature 313:756-761; 1985. 230 Ullrich A, Gray A, Tam AW, Yang-Feng T, Tsubokawa M, Jacobs S, Francke U, Ramachandran J, Fujita-Yamaguchi Y: Insulin-like growth factor I receptor primary structure: Comparison with insulin receptor suggests structural determinants that define functional specificity. EMBO J 5:2503-2512; 1986. 231 Ullrich A, Schlessinger J: Signal transduction by receptors with tyrosine tdnase activity. Ceil 61:202-212;1990. 232 Varticovski L, Drucker B, Morrison D, Cantley L, Roberts T: The colony stimulating factor- 1 receptor associates with and activates phosphatidylinositol-3 kinase. Nature 342: 699-702;1989. 233 Velazquez L, Fellous M, Stark GR: Pellegrini S: A protein tyrosine kinase in the interferon ct/13 signaling pathway. Cell 70:313-322; 1992. 234 Vogel US, Dixon RAF, Schaber MD, Diehl RE, Marshall MS, Scolnick EM, Gibbs JB: Cloning of bovine GAP and its interaction with oncogenic ras p21. Nature 335:90-93; 1988. 235 Volpp BD, NauseefWM, Donelson JE, Moser DR, Clark RA: Cloning of the cDNA and functional expression of the 47-kD cytosolic component of human neutrophil respiratory burst oxidase. Proc Natl Aead Sei USA 86: 7195-7199;1989. 236 Wages DS, Keeper J, Rail TB, Weber MJ: Mutations in the SH3 domain of the src oncogene which decrease association ofphosphatidylinositol 3-kinase activity with p p 6 0 v-src and alter ceil morphology. J Virol 66:18661874; 1992.

237 Wahl MI, Nishibe S, Suh PG, Rhee SG, Carpenter G: Epidermal gro,~¢hfactor stimulates tyrosine phosphorylation of phospholipase C (II) independently of receptor internalization and extracellular calcium. Proc Natl Acad Sci USA 86:1568-1572;1989. 238 Waksman G, Kominos D, Robertson SC, Pant N, Baltimore D, Birge RB, Cowburn D, Hanafusa H, Mayer BJ, Overduin M, Resh MD, Rios CB, Silverman L, Kuriyan J: Crystal structure of the phosphotyrosine recognition domain of v-src complexes with tyrosinephosphorylated peptides. Nature 358:645653;1992. 239 Wang LH: The ros oncogene; in Reddy EP, Skalka AM, Curran T (eds): The Oncogene Handbook. Amsterdam, Elsevier, 135-148; 1988. 240 Wang LH, Hanafusa H, Noter MFD, Balduzzi PC: Genetic structure and transforming sequence of avian sarcoma virus UR2. J Virol 41:833-841;1982. 241 Wang LH, Lin B, Jong SM, Dixon D, Ellis L, Roth RA, Rutter WJ: Activation of trnsforming potential of the human insulin receptor gene. Pmc Natt Acad Sci USA 84:5725-5729; 1987. 242 Wasenius VM, Saraste M, Salven P, Eramaa M, Holm L, Lehto ~P: Primary structure of the brain a-spectrin. J Cell Biol 108:79-93; 1989. 243 Wen D, Peles E, Cupples R, Suggs SV, Bacus SS, Luo Y, Trail G, Hu S, Silbiger SM, Levy RB, Koski RA, Lu HS, Yardan Y: Neu differentiation factor: A transmembrane glycoprotein containing an EGF domain and an immtmoglobulin homology unit. Ceil 69:559572;1992. 244 Westermark B, Heldhl CH: Activation ofproto-oncogenes coding for growth factors or growth factor receptors; in Klein G (ed): Cellular Oncogene Activation. New York, Marcel Dekker, 149-180;I988. 245 Whitman MD, Dowries CP, Keeler M, Keller T, Cantley L: Type I phosphatidylinositoI kinase makes a novel inositol phospholipid, phosphatidylinositol-3-phosphate. Nature 332:644-646;1988. 246 Whitman M, Kaplan D, Roberts T, Cantley L: Evidence for two distinct phosphatidylinositot kinases in fibroblasts: Implication for cellular regulation. Biochem J 247:165-t74; 1987. 247 Whitman M, Kaplan DR, Schaffhausen B, Cantley L, Roberts TM: Association of phosphatidylinositol kinase activity with polyoma middle-T competent for transformation. Nature 315:239-242;I985. 248 Williams DE, Eisenman J, Baird A, Ranch C, Ness KV, March CJ, Park LS, Martin V, Mochizuki DY, Bosusell HS, Burgess GS, Cosman D, Lyman SD: Identification of a ligand for the c-kit proto-oncogene. Cell 63: 16%174;i990. 249 Williams LT: Signal transduction by the platelet-derived growth factor receptor. Science 243:1564-1570; 1989.

81

250 Wong G, Muller O, Clark R, Conroy L, Moran MF, Polakis P, McCormick F: Molecular cloning and nucleic binding properties of the GAP-associated tyrosine phosphoprotein p62. Cell 69:551-558; 1992. 251 Wood KW, Samecki C, Roberts TM, Blenis J: ras mediates nerve growth factor receptor modulation of three signal-transducing protein kinases: MAP kinase, raft1, and rsk. Cell 68:1041-1050;1992. 252 Wu H, Reynolds AB, Kanner AB, Vines RR, Parsons JT: Identification and characterization of a novel cytoskeleton-associated pp60src. Mol Cell Biol 11:5113-5124; 1991. 253 Xu G, Boris L, Tanaka K, Dunn D, Wood D, Gesteland R, White R, Weiss R, Tamanoi F: The catalytic domain of the neurofibromatosis type I gene product stimulates ras GTPase and complement ira mutants ofS. cerevisiae. Cell 63:835-841;1990.

254 Xu G, O'ConneU P, Viskochil D, Cawthon R, Robertson M, Culver M, Dtmn D, Stevens J, Gesteland R, White R, Weiss R: The neurofibromatosis type I gene encodes a protein related to GAP. Cell 62:599-608;1990. 255 Yamamoto T, Hihara H, Nishda T, Kawai S, Toyoshima K: A new avian erythroblastosis virus, AEV-H carries erbB gene responsible for the induction of both erythroblastosis and sarcomas. Cell 34:225-234;1983. 256 Yamanashi Y, Fukui Y, Wongsasant B, Kinoshita Y, Ichimori Y, Toyoshima K, Yamamoto T: Activation of Src-like protein-tyrosine kinase Lyn and its association with phosphatidylinositol 3-kinase upon B-ceU antigen receptor-mediated signaling. Proc Natl Acad Sci USA 89:1118-1122; 1992.

257 Yamanashi Y, Okada M, Semba T, Yamori T, Umemori H, Tsunasawa S, Toyoshima K, Kitamura D, Watanabe T, Yamamoto T: Identification of HS 1 protein as a major substrate for protein-tyrosine kinases upon B-cell antigen receptor-mediated signaling. Proc Natl Acad Sci USA 90:3631-3635; 1993. 258 Yarden Y, Kuang WJ, Yang-Feng T, Coussens L, Munemitsu S, Dull T J, Chert E, Schlessinger J, Franckie U, Ullrich A: Human protooncogene c-kit: A new cell surface receptor tyrosine kinase for an unindentified ligand. EMBO J 6:3341-3351; 1987. 259 Yarden J, Schlessinger J: Epidermal growth factor induces rapid, reversible aggregation of the purified epidermal growth factor receptor. Biochemistry 26:1443-1451; 1987. 260 Zheng XM, Wang Y, PaUen CJ: Cell transformation and activation of pp60c-sr¢by overexpression of a protein tyrosine phosphatase. Nature 359:336-339; 1992.

82

Liu/Wang

Signal Transduction by Protein Tyrosine Kinases